Charged particle device and charged particle apparatus

Abstract

A charged particle device for projecting a plurality of beams of charged particles toward a sample is provided. The apparatus includes a plurality of sources configured to emit respective source beams of charged particles toward a sample along respective paths of a beam grid including a plurality of charged particle beams. The device also includes one or more elements in which an array of apertures is defined. The one or more elements each include a plurality of beam regions assigned to individual source beams. The one or more elements are configured to operate on a charged particle beam in a beam grid of individual source beams. Each element is separated from an adjoining element by a spacer having at least one aperture positioned to correspond to a position of at least two beam regions.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of EP application 22215638.2 filed on December 21, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The embodiments provided herein generally relate to a charged particle device and a charged particle apparatus including the charged particle device. Background Art

[0004] When manufacturing semiconductor integrated circuit (IC) chips, due to, for example, optical effects and accidental particles, undesired pattern defects inevitably occur on the substrate (i.e., wafer) or mask during the manufacturing process, thereby reducing the yield. Therefore, monitoring the degree of undesired pattern defects is an important process in IC chip manufacturing. More generally, for example, the evaluation (such as inspection and / or measurement) of a substrate surface or other object / material is an important process during and / or after its manufacturing.

[0005] Pattern evaluation systems with charged particle beams have been used to inspect objects, such as detecting pattern defects and measuring structural features on such objects. These tools typically use electron microscopy techniques, such as using an electron optical system in a scanning electron microscope (SEM). In an exemplary electron optical system such as an SEM, a primary electron beam of relatively high energy is targeted at a final deceleration step so as to land on the sample at a relatively low landing energy. The electron beam is focused onto the sample as a probe spot. The interaction between the material structure at the probe spot and the landing electrons from the electron beam causes electrons to be emitted from the surface, such as secondary electrons, backscattered electrons, or Auger electrons. The generated secondary electrons can be emitted from the material structure of the sample. By scanning the primary electron beam as a probe spot on or across the sample surface, secondary electrons can be emitted across the sample surface. By collecting these emitted secondary electrons from the sample surface, the pattern evaluation system (or evaluation tool) can obtain an image representing the characteristics of the material structure of the sample surface. The intensity of the electron beam including backscattered electrons and secondary electrons can vary based on the nature of the internal and external structures of the sample, thereby indicating whether the sample is defective.

[0006] It is desired to increase the throughput of an evaluation system, such as for inspection, so that samples can be processed more quickly. In particular, it is desired to increase the throughput, for example, one wafer per hour. One technique for increasing the throughput of an evaluation system is to increase the number of charged particle devices (also referred to as columns) that are positioned to scan each sample. However, there remains a problem in that the space in the evaluation system is limited, for example, in the evaluation device part of the evaluation system, such as the number of charged particle devices that can be accommodated in the evaluation device to scan samples of typical size. Such an evaluation system can be located in the production facilities of a chip fabrication plant, which may impose practical limitations on the size (e.g., footprint) of the evaluation. It is desired that the footprint of the system in the production facility be as small as possible. Accordingly, the present invention aims to increase the throughput of samples, for example, to address these constraints. Summary of the Invention

[0007] An object of the present disclosure is to provide embodiments of a charged particle device and a charged particle apparatus.

[0008] According to a first aspect of the present invention, there is provided a charged particle device for projecting a plurality of beams of charged particles towards a sample. The device includes a plurality of sources configured to emit respective source beams of charged particles along respective paths of a beam grid including a plurality of charged particle beams towards the sample. The device further includes one or more elements in which an aperture array is defined. The one or more elements each include a plurality of beam regions assigned to respective source beams. The one or more elements are configured to operate on the charged particle beams in the beam grid of the respective source beams. Each element is separated from an adjacent element by a spacer having at least one aperture positioned to correspond to the positions of at least two beam regions.

[0009] According to a second aspect of the present invention, there is provided a charged particle apparatus for projecting a plurality of beams of charged particles towards a sample, the apparatus including the device and a platform configured to support the sample. Brief Description of the Drawings

[0010] The above and other aspects of the present disclosure will become more apparent from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings.

[0011] Figure 1 is a schematic diagram illustrating an exemplary electron beam evaluation apparatus.

[0012] Figure 2 is illustrated as Figure 1 a schematic diagram of an exemplary multi-beam charged particle evaluation system that is part of the exemplary electron beam evaluation apparatus.

[0013] Figure 3 is a schematic diagram of an exemplary multi-beam charged particle device.

[0014] Figure 4It is a schematic diagram of an exemplary electron optical system including a macro collimator and a macro scanning deflector.

[0015] Figure 5 It is a schematic diagram of an exemplary charged particle device including an array of collimator elements and an array of scanning deflectors.

[0016] Figure 6 It is a schematic diagram of an exemplary multi-beam charged particle device.

[0017] Figure 7 It is a schematic diagram providing a plan view of elements of a charged particle device, including a single beam region associated with a beam grid.

[0018] Figure 8 It is a schematic diagram of a charged particle device including a plurality of sub-devices, each sub-device including a charged particle beam source.

[0019] Figures 9A to 9C It is a schematic diagram providing a plan view of elements of a charged particle device, including a plurality of beam regions respectively associated with different beam grids.

[0020] Figure 10 It is a schematic diagram providing a plan view of elements of a charged particle device, including a plurality of beam regions arranged in a plurality of rings around an intermediate region.

[0021] Figure 11 It is a schematic diagram of a charged particle device including a Figure 9B charged particle device having the beam region arrangement shown.

[0022] The schematic diagrams and views illustrate the components described below. However, the components depicted in the drawings are not drawn to scale. Detailed Description

[0023] Now, reference will be made in detail to exemplary embodiments, which are illustrated in the accompanying drawings. The following description refers to the drawings, where the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations set forth in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Rather, these implementations are merely examples of devices and methods consistent with various aspects of the present invention recited in the appended claims.

[0024] The enhanced computing power of an electronic device can be achieved by significantly increasing the packaging density of circuit components (such as transistors, capacitors, diodes, etc.) on an IC chip, which reduces the physical size of the device. This is achieved by increasing the resolution, enabling the fabrication of smaller structures. For example, an IC chip in a smart phone (which is thumbnail-sized and available in 2019 or earlier) can include over 2 billion transistors, each less than 1 / 1000 the size of a human hair. Thus, semiconductor IC manufacturing is a complex and time-consuming process with many individual steps. An error in one of these steps can have a significant impact on the operation of the final product. The goal of the manufacturing process is to increase the overall yield of the process. For example, to achieve a 75% yield for a 50-step process (where one step can indicate the number of layers formed on a wafer), the yield of each individual step must be greater than 99.4%. If the yield of each individual step is 95%, the overall process yield will be as low as 7%.

[0025] While high process yield is required in an IC chip manufacturing facility, it is also essential to maintain a high substrate (i.e., wafer) throughput (defined as the number of substrates processed per hour). The presence of defects can affect both high process yield and high substrate throughput. This is especially true if reviewing the defects requires operator intervention. Therefore, it is important to detect and identify micron- and nano-scale defects at high throughput using an evaluation system (such as or including a scanning electron microscope (‘SEM’)) for maintaining high yield and low cost.

[0026] An SEM includes a scanning device and a detector device. The scanning device includes an irradiation device, which includes an electron source for generating primary electrons and a projection device for scanning a sample (such as a substrate) with one or more focused primary electron beams. At least the irradiation device or irradiation system and the projection device or projection system together can be referred to as an electron optical system or device. The primary electrons interact with the sample and generate secondary electrons. The detection device captures secondary electrons from the sample as the sample is scanned, enabling the SEM to create an image of the scanned area of the sample. Such an evaluation device can utilize a single primary electron beam incident on the sample. For high-throughput inspection, some evaluation devices use multiple focused primary electron beams, i.e., multi-beams. The component beams in a multi-beam can be referred to as sub-beams or beamlets. In a multi-beam arrangement, the sub-beams can be arranged relative to each other within the multi-beam. The multi-beam can scan different parts of the sample simultaneously. Thus, a multi-beam evaluation device can evaluate (such as inspect) a sample at a much higher speed than a single-beam evaluation device.

[0027] The implementation of known multi-beam evaluation devices and systems is described below.

[0028] The accompanying drawings are schematic. Accordingly, for clarity, the relative dimensions of components in the drawings are exaggerated. In the following description of the drawings, like or similar reference numerals refer to like or similar components or entities, and only the differences with respect to each embodiment are described. Although the description and the drawings relate to an electro-optical system, it is to be understood that the embodiments are not used to limit the present disclosure to specific charged particles. Accordingly, references to electrons throughout this document may be more generally considered references to charged particles, which are not necessarily electrons.

[0029] Now referring to Figure 1 , Figure 1 which is a schematic diagram illustrating an exemplary charged particle beam evaluation apparatus 100. It should be noted that the evaluation apparatus includes a part of an evaluation system, typically a part of an evaluation system located in a manufacturing facility. The evaluation apparatus may cover a surface area of the manufacturing facility floor, referred to as the apparatus footprint. Other parts of the evaluation system, such as the vacuum and fluid supply service systems and the remote handling racks, may be located elsewhere in the manufacturing facility, away from other manufacturing systems and equipment with less stringent space requirements.

[0030] Figure 1 The charged particle beam evaluation apparatus 100 of

[0031] includes a main chamber 10, a load lock chamber 20, a charged particle evaluation system 40 (which may also be referred to as an electron beam system or tool), an equipment front end module (EFEM) 30, and a controller 50. The charged particle evaluation system 40 is located within the main chamber 10.

[0032] The load lock chamber 20 is used to remove the gas around the sample. This creates a vacuum where the local air pressure is lower than the pressure in the surrounding environment. The load lock chamber 20 can be connected to a load lock vacuum pump system (not shown), which removes the gas particles in the load lock chamber 20. The operation of the load lock vacuum pump system enables the load lock chamber to reach a first pressure lower than atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) transport the sample from the load lock chamber 20 to the main chamber 10. The main chamber 10 is connected to a main chamber vacuum pump system (not shown). The main chamber vacuum pump system removes the gas particles in the main chamber 10, such that the pressure around the sample reaches a second pressure lower than the first pressure. After reaching the second pressure, the sample is transported to the charged particle evaluation system 40, through which the sample can be evaluated. The charged particle evaluation system 40 includes a charged particle device 41. The charged particle device 41 can be an electron optical device, which can be synonymous with an electron optical system. The charged particle device 41 can be a multi-beam charged particle device 41, configured to project multiple beams, such as sub-beams, arranged relative to each other in a multi-beam arrangement, towards the sample. Alternatively, the charged particle device 41 can be a single-beam charged particle device 41, configured to project a single beam towards the sample.

[0033] The controller 50 is electronically connected to the charged particle evaluation system 40. The controller 50 can be a processor (such as a computer) configured to control the charged particle beam evaluation device 100. The controller 50 can also include processing circuitry configured to perform various signal and image processing functions. Although the controller 50 is shown Figure 1 outside of the structure including the main chamber 10, the load lock chamber 20, and the EFEM 30, it is to be understood that the controller 50 can be part of the structure. The controller 50 can be located in one of the constituent elements of the charged particle beam evaluation device, or the controller 50 can be distributed over at least two constituent elements. While the present disclosure provides an example of the main chamber 10 that houses the electron beam evaluation device, it should be noted that the broadest aspects of the present disclosure are not limited to the chamber that houses the electron beam evaluation device. Instead, it is to be understood that the foregoing principles can also be applied to other tools and other arrangements of devices operating at the second pressure.

[0034] Now referring to Figure 2 , Figure 2 is a schematic diagram illustrating an exemplary charged particle evaluation system 40 including a multi-beam charged particle device 41, which is Figure 1A part of the exemplary charged particle beam evaluation device 100. The multi-beam charged particle device 41 includes an electron source 201 and a projection device 230. The charged particle evaluation system 40 further includes an actuating platform 209 and a sample holder 207. The sample holder may have a holding surface (not depicted) for supporting and holding the sample. Thus, the sample holder can be configured to support the sample. Such a holding surface can be an electrostatic chuck, operable to hold the sample during the operation of the charged particle device 41 (e.g., the evaluation of at least a part of the sample, such as measurement or inspection). The holding surface can be recessed into the sample holder, e.g., the surface of the sample holder oriented to face the charged particle device 41. The electron source 201 and the projection device 230 can be collectively referred to as the charged particle device 41. The sample holder 207 is supported by the actuating platform 209 to hold the sample 208 (e.g., a substrate or a mask) for evaluation. The multi-beam charged particle device 41 further includes a detector 240 (e.g., an electron detection device).

[0035] The electron source 201 may include a cathode (not shown) and an extractor or an anode (not shown). During operation, the electron source 201 is configured to emit electrons from the cathode as primary electrons. The primary electrons are extracted or accelerated by the extractor and / or the anode to form a primary electron beam 202.

[0036] The projection device 230 is configured to convert the primary electron beam 202 into a plurality of sub-beams 211, 212, 213, and direct each sub-beam onto the sample 208. Although three sub-beams are illustrated for simplicity, there may be dozens, hundreds, or thousands of sub-beams. The sub-beams can be referred to as beamlets.

[0037] The controller 50 can be connected to Figure 1 the respective parts of the charged particle beam evaluation device 100, such as the electron source 201, the detector 240, the projection device 230, and the actuating platform 209. The controller 50 can perform various image and signal processing functions. The controller 50 can also generate various control signals to manage the operation of the charged particle beam evaluation device, including the charged particle multi-beam device.

[0038] The projection device 230 can be configured to focus the sub-beams 211, 212, and 213 onto the sample 208 for evaluation and can form three detection spots 221, 222, and 223 on the surface of the sample 208. The projection device 230 can be configured to deflect the primary sub-beams 211, 212, and 213 to scan the detection spots 221, 222, and 223 across respective scan regions in the surface section of the sample 208. In response to the primary sub-beams 211, 212, and 213 being incident on the detection spots 221, 222, and 223 on the sample 208, electrons including secondary electrons and backscattered electrons are generated from the sample 208. The electron energy of the secondary electrons is typically ≤50 eV. The actual secondary electrons can have an energy less than 5 eV, but any energy below 50 eV is generally treated as secondary electrons. The electron energy of the backscattered electrons is typically between 0 eV and the landing energy of the primary sub-beams 211, 212, and 213. Since electrons with a detected energy less than 50 eV are generally regarded as secondary electrons, a certain proportion of the actual backscattered electrons will be counted as secondary electrons.

[0039] The detector 240 is configured to detect signal particles, such as secondary electrons and / or backscattered electrons, and generate corresponding signals, which are sent to the signal processing system 280, for example, to construct an image of the corresponding scan region of the sample 208. The detector 240 can be incorporated into the projection device 230.

[0040] The signal processing system 280 can include circuitry (not shown) that is configured to process the signals from the detector 240 to form an image. The signal processing system 280 can also be referred to as an image processing system. The signal processing system can be incorporated into components of the multi-beam charged particle evaluation system 40, such as the detector 240 (as Figure 2as shown). However, the signal processing system 280 can be incorporated into any component of the evaluation device 100 or the multi-beam charged particle evaluation system 40, such as being part of the projection device 230 or the controller 50. The signal processing system 280 can include an image acquirer (not shown) and a storage device (not shown). For example, the signal processing system can include a processor, a computer, a server, a mainframe, a terminal, a personal computer, any kind of mobile computing device, etc. or a combination thereof. The image acquirer can include at least a part of the processing function of the controller. Thus, the image acquirer can include at least one or more processors. The image acquirer can be communicatively coupled to a detector 240 that allows signal communication, such as an electrical conductor, an optical fiber cable, a portable storage medium, IR, Bluetooth, the Internet, a wireless network, a radio station, etc. or a combination thereof. The image acquirer can receive signals from the detector 240, can process the data included in the signals, and can construct an image therefrom. The image acquirer can thus acquire an image of the sample 208. The image acquirer can also perform various post-processing functions, such as generating contours, superimposing indicators on the acquired image, etc. The image acquirer can be configured to perform adjustments such as the brightness and contrast of the acquired image. The storage device can be a storage medium such as a hard disk, a flash drive, a cloud storage device, a random access memory (RAM), other types of computer-readable memory, etc. The storage device can be coupled to the image acquirer and can be used to save the scanned original image data as the original image and the post-processed image.

[0041] The signal processing system 280 can include measurement circuitry (e.g., an analog-to-digital converter) to obtain the distribution of the detected secondary electrons. The electron distribution data collected during the detection time window can be used in combination with the corresponding scan path data of each of the primary sub-beams 211, 212, and 213 incident on the sample surface to reconstruct an image of the sample structure being evaluated. The reconstructed image can be used to reveal various features of the internal or external structure of the sample 208. Thus, the reconstructed image can be used to reveal any defects that may be present in the sample.

[0042] The controller 50 can control the actuating platform 209 to move the sample 208 during the evaluation (e.g., inspection) of the sample 208. The controller 50 can cause the actuating platform 209 to be able to move the sample 208 in at least one direction (preferably continuously, e.g., at a constant speed) during the sample evaluation. The controller 50 can control the movement of the actuating platform 209 such that the controller 50 changes the movement speed of the sample 208 depending on various parameters. For example, the controller 50 can control the platform speed (including its direction) depending on the characteristics of the evaluation steps of the scanning process.

[0043] Known multi-beam systems (such as the charged particle evaluation system 40 and the charged particle beam evaluation device 100 described above) are disclosed in US2020118784, US20200203116, US2019 / 0259570, and US2019 / 0259564, which are incorporated herein by reference.

[0044] As Figure 2 shown, in an embodiment, the charged particle evaluation system 40 has a single charged particle device 41 and optionally includes a projection assembly 60. The projection assembly 60 can be a module and can be referred to as an ACC module. The projection assembly 60 is arranged to direct a light beam 62 such that the light beam 62 enters between the charged particle device 41 and the sample 208.

[0045] When the electron beam scans the sample 208, due to the large beam current, charges may accumulate on the sample 208, which may affect the image quality. To adjust the accumulated charges on the sample, the projection assembly 60 can be used to irradiate the light beam 62 onto the sample 208 to control the accumulated charges caused by effects such as photoconductivity, photoelectric, or thermal effects.

[0046] The following Figure 3 describes the components of the charged particle evaluation system 40 that can be used in the present invention. Figure 3 is a schematic diagram of the charged particle evaluation system 40. Figure 3 The charged particle evaluation system 40 of

[0047] The electron source 201 directs electrons towards an array of condenser lenses 231 (also referred to as a condenser lens array). The electron source 201 is desirably a high-brightness emitter and is arranged to operate within an optimized electron optical performance range, which is a trade-off between brightness and total emission current (this trade-off can be considered a 'good' trade-off). The electron source emits a source beam. There can be dozens, hundreds, or thousands or even tens of thousands of condenser lenses 231. The condenser lenses 231 can include multi-electrode lenses and have a configuration based on EP1602121A1, which is incorporated herein by reference particularly for the disclosure of a lens array that splits the source beam into multiple sub-beams. The most upstream plate (which can be referred to as a beam-limiting aperture array and can be the most upstream plate of the condenser lens array) can generate multiple beams. The array of condenser lenses (which can include the beam-limiting aperture array) can provide lenses for each sub-beam. The condenser lens array 231 can take the form of at least two plates that act as electrodes, with the apertures in each plate aligned with each other and corresponding to the positions of the sub-beams. The at least two plates are maintained at different potentials during operation to achieve the desired lens effect.

[0048] In one arrangement, the focusing lens array 231 is formed from three plate arrays where charged particles have the same energy when entering and leaving each lens, and this arrangement can be referred to as an Einzel lens. Thus, dispersion occurs only within the Einzel lens itself (between the entrance and exit electrodes of the lens), thereby limiting off-axis chromatic aberration. When the thickness of the focusing lens is low (e.g., a few millimeters), the effect of this aberration is small or negligible.

[0049] Each focusing lens 231 in the array directs electrons into respective sub-beams 211, 212, 213 which are focused at respective intermediate foci downstream of the focusing lens array. The sub-beams diverge relative to each other. In an embodiment, a deflector 235 is provided at the intermediate foci. The deflector 235 is positioned in the sub-beam path at or at least around the location of the corresponding intermediate focus. The deflector 235 is positioned in or near the sub-beam path at the intermediate image plane of the associated sub-beam. The deflector 235 is configured to operate on the respective sub-beams 211, 2,12, 213. The deflector 235 is configured to bend the respective sub-beams 211, 212, 213 by an amount to effectively ensure that the principal ray (which can also be referred to as the beam axis) impinges on the sample 208 substantially normally (i.e., at substantially 90° to the nominal surface of the sample). The deflector 235 can also be referred to as a collimator or a collimator deflector. The deflector 235 effectively collimates the paths of the sub-beams such that upstream of the deflector, the sub-beam paths diverge relative to each other. Downstream of the deflector, the sub-beam paths are substantially parallel to each other, i.e., substantially collimated. A suitable collimator is the deflector disclosed in EP application 20156253.5 filed on 7 February 2020, which is incorporated herein by reference relative to the application of the deflector to a multi-beam array. In an embodiment of this arrangement, the collimator can include a macroscopic collimator instead of the deflector 235 or in addition to the deflector 235. The macroscopic collimator can be electrostatic, for example as two or more flat plates with a single aperture.

[0050] There is a control lens array 250 below (i.e., downstream or further from the source 201) the deflector 235. The sub-beams 211, 212, 213 passing through the deflector 235 are substantially parallel when entering the control lens array 250. The control lenses pre-focus the sub-beams (e.g., apply a focusing action to the sub-beams before the sub-beams reach the objective lens array 241). The pre-focusing can reduce the divergence of the sub-beams or increase the rate of convergence of the sub-beams. The control lens array 250 and the objective lens array 241 operate together to provide a combined focal length. The combined operation without an intermediate focus can reduce the risk of aberration. In an embodiment, the control lenses in the control lens array can be considered as part of the objective lenses in the objective lens array. The electrode plates of the control lens array can be considered as additional electrode plates of the objective lens array in terms of electron optics.

[0051] It is desirable to use the control lens array 250 to determine the landing energy. However, the objective lens array 241 can alternatively be used to control the landing energy. In this case, when different landing energies are selected, the potential difference across the objective lens changes. An example of a situation where it is desirable to partially change the landing energy by varying the potential difference across the objective lens is to prevent the focus of the sub-beams from being too close to the objective lens. In this case, there is a risk that the components of the objective lens array 241 are too thin to fabricate. The same may be true for the detector at that location. For example, this may occur when the landing energy is reduced. This is because the focal length of the objective lens is approximately proportional to the landing energy used. By reducing the potential difference across the objective lens, and thus reducing the electric field within the objective lens, the focal length of the objective lens becomes larger again, causing the focus position to be further below the objective lens. Note that using only the objective lens limits the control of the magnification. This arrangement cannot control the demagnification ratio and / or the opening angle. Further, using the objective lens to control the landing energy may mean that the objective lens will operate away from its optimal field strength. That is, unless the mechanical parameters of the objective lens (such as the spacing between its electrodes) can be adjusted, for example by replacing the objective lens.

[0052] The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to respective potential sources. The control lens array 250 can include two or more (e.g., three) plate electrode arrays connected to respective potential sources. The control lens array 250 is associated with the objective lens array 241 (e.g., these two arrays are positioned close to each other and / or mechanically connected to each other and / or controlled together as a unit). Each control lens can be associated with a respective objective lens. The control lens array 250 is positioned upstream of the objective lens array 241.

[0053] The control lens array 250 includes control lenses for each of the sub-beams 211, 212, 213. The function of the control lens array 250 is to optimize the beam opening angle relative to the demagnification ratio of the beam and / or to control the beam energy delivered to the objective lens array 241, which directs the sub-beams 211, 212, 213 onto the sample 208. The objective lens array 241 can be positioned at or near the base of the charged particle device 41. The control lens array 250 is optional but is preferably used to optimize the sub-beams upstream of the objective lens array. In one arrangement, the control lens array 250 can be considered part of the objective lens array. The plates of the control lens array can be regarded as additional plates of the objective lens array. Within the objective lens array that meets this definition, in addition to the functions of the objective lens array described herein, the functions of the control lens array can also be a function of the objective lens array.

[0054] For ease of illustration, the lens arrays are schematically depicted herein as oval arrays as Figure 3 shown and as Figure 5 and6 In terms of). Each ellipse represents one lens in the lens array. By convention, ellipses are used to represent lenses, similar to the biconvex form often employed in optical lenses. However, in the context of charged particle arrangements such as those discussed herein, it is to be understood that the lens array will typically operate electrostatically and thus may not require any physical elements in the biconvex shape. The lens array may instead comprise a plurality of plates having apertures.

[0055] A scanning deflector array 260 may be provided between the control lens array 250 and the objective lens array 234. The scanning deflector array 260 includes scanning deflectors for each of the sub-beams 211, 212, 213. Each scanning deflector is configured to deflect the corresponding sub-beam 211, 212, 213 in one or two directions so as to scan the sub-beams across the sample 208 in one or two directions.

[0056] As Figure 3 shown, the schematic diagram of an exemplary charged particle device has an objective lens array assembly. The objective lens array assembly includes an objective lens array 241. The objective lens array 241 includes a plurality of objective lenses. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a corresponding potential source. The objective lens array 241 may include two or more (e.g., three) plate electrode arrays connected to corresponding potential sources. Each objective lens formed by the plate electrode array may be a microlens that operates on different sub-beams or groups of sub-beams in a multi-beam. Each plate defines a plurality of apertures (which may also be referred to as holes). The position of each aperture in a plate corresponds to the position of a corresponding aperture (or corresponding hole) in another plate (or plurality of plates). The corresponding apertures define the objective lens, and thus each set of corresponding holes operates on the same sub-beam or group of sub-beams in the multi-beam in use. Each objective lens projects the corresponding sub-beam of the multi-beam onto the sample 208.

[0057] The objective lens array assembly further includes a control lens array 250. The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a corresponding potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to corresponding potential sources. The control lens array 250 is associated with the objective lens array 241 (e.g., these two arrays are positioned close to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is positioned upstream of the objective lens array 241. The control lens pre-focuses the sub-beams (e.g., applies a focusing action to the sub-beams before the sub-beams reach the objective lens array 241). Pre-focusing can reduce the divergence of the sub-beams or increase the convergence rate of the sub-beams. The control lens array and the objective lens array operate together to provide a combined focal length. The combined operation without an intermediate focus can reduce the risk of aberration. In an embodiment, the control lens array may be considered part of the objective lens array.

[0058] In Figure 3 the arrangement, the objective lens array assembly includes a scan deflector array 260. The scan deflector array 260 includes a plurality of scan deflectors. The scan deflector array 260 can be formed using MEMS manufacturing techniques. Each scan deflector scans a corresponding sub-beam over or across the sample 208. Thus, the scan deflector array 260 can include a scan deflector for each sub-beam. Each scan deflector can deflect the light in the sub-beam in one direction (e.g., parallel to a single axis, such as the X-axis) or in two directions (e.g., relative to two non-parallel axes, such as the X and Y axes). Deflection causes the sub-beam to be scanned across the sample 208 along one or two directions (i.e., one-dimensionally or two-dimensionally). In an embodiment, the scan deflectors described in EP2425444 can be used to implement the scan deflector array 260, which document is specifically about scan deflectors and is hereby incorporated by reference in its entirety. The scan deflector array 260 is positioned between the objective lens array 241 and the control lens array 250. In the illustrated embodiment, the scan deflector array 260 is provided in place of a macroscopic scan deflector, such as an electrostatic scan deflector (not shown). Compared with the macroscopic scan deflector, the scan deflector array 260 can be more spatially compact.

[0059] The objective lens array assembly can include a detector 240. (Alternatively, the detector can be included in the charged particle device 41 and need not be present in the objective lens array assembly). The detector 240 can include detector elements (e.g., sensor elements, such as capture electrodes). The detector 240 can include any suitable type of detector. For example, the detector element can be: a charge-based detector configured to detect the charge detected over time (e.g., as a current), a scintillator, or a semiconductor device such as a PIN element. The detector 240 can be a DC detector or an indirect current detector.

[0060] The detector 240 can be positioned between the objective lens array 241 and the sample 208. The detector 240 is configured as the most downstream feature of the electro-optical device, e.g., close to the sample 208. The detector 240 can be very close to the sample 208, e.g., less than 5 mm, 3 mm, 1.5 mm, 300 μm, preferably between 200 and 10 μm, more preferably between 100 and 30 μm, e.g., between 40 and 70 μm.

[0061] The detector 240 may be positioned within the device so as to face the sample 208. Alternatively or additionally, the detector 240 may be positioned elsewhere within the electron optical system 41 such that a part of the electron optical device that faces the sample 208 is different from (and thus not) the detector, such as an electrode of the objective lens arrangement. In such an arrangement, another element of the electron optical device may face the sample during operation, such as the electrode plate of the objective lens. In all such arrangements, there is a most downstream element of the electron optical system that is closest to the sample (such as the detector 240). The most downstream surface of the most downstream element may face the sample. The most downstream surface may be referred to as the facing surface.

[0062] The bottom surface of the detector 240 (or the facing surface of the detector 240 that may face the sample 208 in use) may include a substrate on which a plurality of detector elements are provided. Each detector element may surround a beam aperture. The beam aperture may be formed by etching through the substrate. In such an arrangement, the beam apertures are in a hexagonal close-packed array or, alternatively, in a rectangular array. The detector elements may be arranged in a rectangular array or a hexagonal array.

[0063] In a cross-section of the detector, the detector elements form the bottommost (i.e., closest to the sample 208) surface of the detector 240. A logic layer may be provided between the detector elements and the substrate body. At least a part of the signal processing system may be incorporated into the logic layer. A wiring layer is provided on the back or inside of the substrate and is connected to the logic layer via substrate vias. The wiring layer may include control lines, data lines, and power lines. A printed circuit board and / or other semiconductor chips may be provided on the back of the detector 240, for example, connected to the back of the detector 240.

[0064] The detector 240 may be implemented by integrating a CMOS chip detector into an electrode of the objective lens array 241, such as the bottom electrode of the objective lens array 241. Integrating the detector 240 into the objective lens array 241 or other components of the electron optical system 41 allows for the detection of electrons emitted with respect to a plurality of corresponding sub-beams. The CMOS chip may implement the detector, which may be oriented to face the sample. In an embodiment, detector elements for capturing secondary charged particles are formed in the top metal layer of the CMOS device. The detector elements may be formed in other layers. The power and control signals of the CMOS may be connected to the CMOS via silicon vias. A passive silicon substrate with holes shields the CMOS chip from high electric fields, for example, providing robustness.

[0065] To maximize detection efficiency, it is desirable to make the surface of the detector element as large as possible such that substantially all of the area of the objective lens array 240 (except for the apertures) is occupied by the detector element. Additionally or alternatively, the diameter of each detector element is substantially equal to the array pitch (i.e., the aperture pitch of the aperture array in the electrodes of the objective lens assembly 241). The diameter of each detector element can be less than about 600 μm and preferably between about 50 μm and 500 μm. The pitch can be selected depending on the expected distance between the sample 208 and the detector 240. In an embodiment, the profile of the detector element is circular, but it can also be made square to maximize the detection area. The diameter of the substrate vias can be minimized. The typical size of the electron beam is about 5 to 15 μm.

[0066] In an embodiment, a single detector element surrounds each beam aperture. In another embodiment, multiple detector elements are provided around each beam aperture.

[0067] Figure 4 is a schematic diagram of an exemplary electron optical system having an objective lens array assembly. The objective lens array assembly includes an objective lens array 241. The objective lens array 241 includes a plurality of objective lenses. Each objective lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The objective lens array 241 can include two or more (e.g., three) arrays of plate electrodes connected to respective potential sources. Each objective lens formed by the array of plate electrodes can be a microlens that operates on different sub-beams or groups of sub-beams in a multi-beam. Each plate defines a plurality of apertures (which can also be referred to as holes). The position of each aperture in a plate corresponds to the position of a corresponding aperture (or corresponding hole) in another plate (or plates). The corresponding apertures define the objective lens, and thus each set of corresponding holes operates on the same sub-beam or group of sub-beams in the multi-beam during use. Each objective lens projects a respective sub-beam of the multi-beam onto the sample 208.

[0068] For ease of illustration, the lens array is schematically depicted herein by an array of ellipses. Each ellipse represents one of the lenses in the lens array. By convention, ellipses are used to represent lenses, similar to the biconvex form often employed in optical lenses. However, in the context of charged particle arrangements such as those discussed herein, it is to be understood that the lens array will typically operate electrostatically and thus may not require any physical elements in the biconvex shape. As described above, the lens array can instead include a plurality of plates having apertures.

[0069] The objective lens array assembly further includes a control lens array 250. The control lens array 250 includes a plurality of control lenses. Each control lens includes at least two electrodes (e.g., two or three electrodes) connected to a respective potential source. The control lens array 250 may include two or more (e.g., three) plate electrode arrays connected to respective potential sources. The control lens array 250 is associated with the objective lens array 241 (e.g., the two arrays are positioned close to each other and / or mechanically connected to each other and / or controlled together as a unit). The control lens array 250 is positioned upstream of the objective lens array 241. The control lens pre-focuses the sub-beam (e.g., applies a focusing effect to the sub-beam before the sub-beam reaches the objective lens array 241). The pre-focusing can reduce the divergence of the sub-beam or increase the convergence rate of the sub-beam. The control lens array and the objective lens array operate together to provide a combined focal length. The combined operation without an intermediate focus can reduce the risk of aberration.

[0070] In an embodiment, an electro-optical system including the objective lens array assembly is configured to control the objective lens array assembly (e.g., by controlling the potential applied to the electrodes of the control lens array 250) such that the focal length of the control lens is greater than the spacing between the control lens array 250 and the objective lens array 241. Thus, the control lens array 250 and the objective lens array 241 can be positioned relatively close together, and the focusing effect from the control lens array 250 is too weak to form an intermediate focus between the control lens array 250 and the objective lens array 241. In other embodiments, the objective lens array assembly may be configured to form an intermediate focus between the control lens array 250 and the objective lens array 241.

[0071] In an embodiment, the control lens array is a replaceable module, either alone or in combination with other elements such as an objective lens array and / or a detector array. The replaceable module may be field replaceable, i.e., a field engineer can swap the module for a new one. In an embodiment, a plurality of replaceable modules are included within a tool and can be swapped between an operable position and an inoperable position without opening the tool.

[0072] In an embodiment, the replaceable module includes an electro-optical component that is located on a platform that allows actuation to position the component. In an embodiment, the replaceable module includes a platform. In one arrangement, the platform and the replaceable module can be an integral part of the charged particle device 41. In one arrangement, the replaceable module is limited to the platform it is supported on and the electro-optical device. In one arrangement, the platform is removable. In an alternative design, the replaceable module including the platform is removable. A portion of the electro-optical tool 40 for the replaceable module is isolatable, i.e., a portion of the charged particle system 40 is defined by a valve upstream and a valve downstream of the replaceable module. The valves can be operated to isolate the environment between the valves from the vacuum upstream and downstream of the valves respectively, enabling the replaceable module to be removed from the charged particle system 40 while maintaining the vacuum upstream and downstream of the column portion associated with the replaceable module. In an embodiment, the replaceable module includes a platform. The platform is configured to support the electro-optical device relative to the beam path. In an embodiment, the module includes one or more actuators. The actuators are associated with the platform. The actuators are configured to move the electro-optical device relative to the beam path. Such actuation can be used to align the electro-optical device and the beam path relative to each other.

[0073] In an embodiment, the replaceable module is a MEMS module. In an embodiment, the replaceable module is configured to be replaceable within the charged particle device 41. In an embodiment, the replaceable module is configured to be field replaceable. Field replaceable is intended to mean that the module can be removed and replaced with the same or a different module while maintaining the vacuum in which the charged particle device 41 is located. Only the section of the column corresponding to the module is vented in order to remove and retract or replace the module.

[0074] The control lens array can be in the same module as the objective lens array 241, i.e., form an objective lens array assembly or an objective lens arrangement, or the control lens array can be in a separate module.

[0075] A power supply can be provided to apply corresponding potentials to the electrodes of the control lenses in the control lens array 250 and the objective lenses in the objective lens array 241.

[0076] In addition to the objective lens array 241, providing the control lens array 250 provides additional degrees of freedom for controlling the properties of the sub-beams. Even when the control lens array 250 and the objective lens array 241 are provided relatively close together, additional degrees of freedom are provided, such as not forming an intermediate focus between the control lens array 250 and the objective lens array 241. The control lens array 250 can be used to optimize the beam opening angle relative to the beam reduction ratio and / or control the beam energy delivered to the objective lens array 241. The control lens can include two or three or more electrodes. If there are two electrodes, then the reduction ratio and the landing energy will be controlled together. If there are three or more electrodes, the reduction ratio and the landing energy can be controlled independently. Thus, the control lens can be configured to adjust the reduction ratio and / or the beam opening angle of the corresponding sub-beam (e.g., by applying appropriate respective potentials to the electrodes of the control lens and the objective lens using a power supply). This optimization can be achieved without unduly negatively affecting the number of objective lenses and without unduly reducing the aberration of the objective lenses (e.g., without increasing the intensity of the objective lenses).

[0077] In Figure 4 an embodiment of, the electron optical system includes a source 201. The source 201 provides a beam of charged particles (e.g., electrons). The multi-beams focused on the sample 208 are derived from the beam provided by the source 201. For example, sub-beams can be derived from the beam using a beam limiter that defines a beam-limiting aperture array. The source 201 is desirably a high-brightness thermal field emitter having a good compromise between brightness and total emission current. In the illustrated example, a collimator is provided upstream of the objective lens array assembly. The collimator can include a macro-collimator 270. The macro-collimator 270 acts on the beam from the source 201 before the beam is split into multi-beams. The macro-collimator 270 bends the corresponding portions of the beam by a certain amount to effectively ensure that the beam axis of each sub-beam derived from the beam is incident on the sample 208 substantially normally (i.e., substantially at 90° to the nominal surface of the sample 208). The macro-collimator 270 applies macro-collimation to the beam. Thus, the macro-collimator 270 can act on all beams, rather than including an array of collimator elements, each configured to act on a different individual portion of the beam. The macro-collimator 270 can include a magnetic lens or a magnetic lens arrangement that includes a plurality of magnetic lens sub-units (e.g., a plurality of electromagnets forming a multipole arrangement). Alternatively or additionally, the macro-collimator can be at least partially electrostatically implemented, e.g., fully electrostatically implemented. The macro-collimator can include an electrostatic lens or an electrostatic lens arrangement that includes a plurality of electrostatic lens sub-units. The macro-collimator 270 can use a combination of a magnetic lens and an electrostatic lens. Desirably, the macro-collimator 270 uses only an electrostatic lens.

[0078] In Figure 4In an embodiment, a macro scan deflector 265 is provided to scan the sub-beams over the sample 208. The macro scan deflector 265 deflects the corresponding portions of the beam to scan the sub-beams over the sample 208. In an embodiment, the macro scan deflector 256 includes a macro multipole deflector, such as having 8 or more poles. The macro scan deflector can be electrostatic or magnetic. The deflection scans the sub-beams derived from the beam in one direction (e.g., parallel to a single axis, such as the X-axis) or in two directions (e.g., relative to two non-parallel axes, such as the X-axis and the Y-axis) across the sample 208. The macro scan deflector 265 acts macroscopically on all the beams, rather than including an array of deflector elements, each configured to act on a different individual portion of the beam. In the illustrated embodiment, the macro scan deflector 265 is provided between the macro collimator 270 and the control lens array 250.

[0079] Figure 4 The electron optical system further includes a detector (not shown), such as the detector 240 described above with respect to Figure 3 Described detector, desirably, the detector can be a detector array.

[0080] In some embodiments, as Figure 5 Illustrated, the control lens array 250 is the first deflective or lensing electron optical array element in the beam path downstream of the source 201. Such an embodiment may have a first beam limiting array 252 to generate a plurality of beams from, for example, the source beam emitted from the source 201. The beam limiting array 252 can be the first electron optical element downstream of the source 201. The control lens array 250 may include the beam limiting array 252.

[0081] In Figure 5 In an embodiment, an array of collimator elements 271 is provided in place of the macro collimator, which can be an electrostatic collimator of two or more plates with a single aperture (which can be in the form of a macro collimating lens, such as an electrostatic lens). Compared to the macro collimator 270, the array of collimator elements 271 can be more spatially compact. Thus, providing the array of collimator elements 271 and the scan deflector array 260 together can provide a space saving. When such a space saving is desired for a case where multiple electron optical systems including an objective lens array assembly are provided in an electron optical system array. In such an embodiment, there may be no macro focusing lens or focusing lens array. In such a scenario, the control lens thus provides the possibility of optimizing the beam opening angle and magnification for variations in landing energy.

[0082] In some embodiments, as Figure 5 Illustrated, the array of collimator elements 271 is the first deflective or focusing electron optical array element in the beam path downstream of the source 201.

[0083] Avoiding any deflection or lensing of the electron optical array elements (such as a lens array or deflector array) upstream of the control lens array 250 or upstream of the collimator element array 271 reduces the requirements for the electron optics upstream of the objective lens and reduces the requirements for the corrector to correct for defects in such optics. For example, some alternative arrangements attempt to maximize source current utilization by providing a converging lens array outside the objective lens array. Providing the converging lens array and the objective lens array in this way results in strict requirements for the position uniformity of the virtual source position over the source opening angle, or requires correction optics for each sub-beam to ensure that each sub-beam passes through the center downstream of its corresponding objective lens. Architectures such as Figure 5 allow the beam path from the first deflected or lensed electron optical array element to the beam shaping limiter 242 to be reduced to less than about 10 mm, preferably less than about 5 mm, and preferably less than about 2 mm. Reducing the beam path reduces or eliminates the strict requirements for the virtual source position over the source opening angle.

[0084] Providing a scanning deflector array 260 instead of a macroscopic scanning deflector can reduce the aberration from the control lens. This is because the scanning action of the macroscopic scanning deflector causes the beam to move correspondingly on the beam shaping limiter (also known as the lower beam limiter), which defines the beam limiting aperture array downstream of at least one electrode of the control lens, which increases the contribution of the control lens to the aberration. When the scanning deflector array 260 is used, the amount of movement of the beam on the beam shaping limiter is much smaller. This is because the distance from the scanning deflector array 260 to the beam shaping limiter is much shorter. Therefore, the scanning deflector array 260 is preferably positioned as close as possible to the objective lens array 241 (such as Figure 5Depicted such that the scan deflector array 260 is directly adjacent to the objective lens array 241. A smaller movement on the beam shaping limiter results in a smaller used portion of each control lens. Accordingly, the control lens has a smaller aberration contribution. To minimize or at least reduce the aberration caused by the control lens, the beam shaping limiter is used to shape the beam downstream of at least one electrode of the control lens. This is architecturally different from conventional systems where the beam shaping limiter is provided only as an aperture array that is part of or associated with the first manipulator array in the beam path and typically generates multiple beams from a single beam from the source. In one arrangement, the beam shaping limiter 242 is structurally integrated with the electrodes of the objective lens array 241. Desirably, the beam shaping limiter 242 is positioned in a region of low electrostatic field strength. Each beam limiting aperture in the beam shaping limiter 242 is aligned with a corresponding objective lens in the objective lens array 241. The alignment enables a portion of the sub-beam from the corresponding objective lens to pass through the beam limiting aperture and impinge on the sample 208. Each beam limiting aperture has a beam limiting effect that allows only a selected portion of the sub-beam incident on the beam shaping limiter 242 to pass through the beam limiting aperture. The selected portion can be such that only a portion of the central part of the corresponding sub-beam passing through the corresponding aperture in the objective lens array reaches the sample. The central part can have a circular cross-section and / or be centered on the beam axis of the sub-beam.

[0085] In other embodiments, for example, variations of the arrangement shown and described provide a macro scan deflector 265 and a scan deflector array 260. In such an arrangement, the scanning of the sub-beams on the sample surface can be achieved by jointly (preferably synchronously) controlling the macro scan deflector and the scan deflector array 260. The variations can include a macro collimator 270 and a collimator array 271, through column distribution collimation action. Figures 4 to 5

[0086] ​In an embodiment, an array of electron optical systems is provided. The array may include any plurality of electron optical systems as described herein. Each electron optical system in the electron optical systems focuses a corresponding plurality of beams simultaneously onto different regions of the same sample. Each electron optical system may form a sub-beam from a charged particle beam from a different corresponding source 201. Each corresponding source 201 may be one of a plurality of sources 201. At least a subset of the plurality of sources 201 may be provided as a source array. The source array may include a plurality of sources 201 provided on a common substrate. Focusing a plurality of pluralities of beams simultaneously onto different regions of the same sample allows for simultaneous processing (e.g., evaluation) of an increased area of the sample 208. The electron optical systems in the array may be arranged adjacent to each other to project the corresponding pluralities of beams onto adjacent regions of the sample 208. Any number of electron optical systems may be used in the array. Preferably, the number of electron optical systems is in the range of 9 to 200. In an embodiment, the electron optical systems are arranged in a rectangular array or a hexagonal array. In other embodiments, the electron optical systems are provided in an irregular array or a regular array having a geometry other than rectangular or hexagonal. When referring to a single electron optical system, each electron optical system in the array may be configured in any of the ways described herein. As mentioned above, the scanning deflector array 260 and the collimator element array 271 are particularly suitable for incorporation into an array of electron optical systems due to their spatial compactness, which helps to position the electron optical systems close to each other.

[0087] In some embodiments, such as, for example, as Figure 5 illustrated, the objective lens array assembly, which is a unit including the objective lens array 241, further includes a beam shaping limiter 242. The beam shaping limiter 242 defines a beam limiting aperture array. The beam shaping limiter 242 may be referred to as a lower beam shaping limiting aperture array or a final beam limiting aperture array. The beam shaping limiter 242 may include a plate (which may be a plate-like body) having a plurality of apertures. The beam shaping limiter 242 is downstream of at least one electrode (optionally all electrodes) of the control lens array 250. In some embodiments, the beam shaping limiter 242 is downstream of at least one electrode (optionally all electrodes) of the objective lens array 241.

[0088] In some embodiments, for example, with reference to Figure 5The charged particle device 41 shown and described also includes an upper beam limiter 252, for example in addition to the beam shaping limiter 242. The upper beam limiter 252 defines a beam limiting aperture array. The upper beam limiter 252 may be referred to as an upper beam limiting aperture array or an upstream beam limiting aperture array. The upper beam limiter 252 may include a plate (which may be plate-shaped) having a plurality of apertures. The upper beam limiter 252 may be a beam limiting array. The upper beam limiter 252 forms sub-beams from the charged particle beam emitted from the source 201. Parts of the beam may be blocked (e.g., absorbed) by the upper beam limiter 252 except for those parts that contribute to the formation of the sub-beams, so as not to interfere with the downstream sub-beams. The charged particles projected through the apertures in the upper beam limiter 252 may be from the sub-beams. The upper beam limiter 252 may be referred to as a sub-beam defining aperture array.

[0089] Any objective lens array assembly described herein may also include a detector 240 having any of the features described. The detector detects electrons emitted from the sample 208. The detected electrons may include any electrons detected by SEM, including secondary and / or backscattered electrons emitted from the sample 208.

[0090] Figure 6 A charged particle evaluation system 40 according to an embodiment is schematically depicted. Features identical to those described above are given the same reference numerals. For the sake of brevity, such features are not described in detail with reference to Figure 6 For example, the source 201, the focusing lens 231, the macro collimator 270, the objective lens array 24, and the sample 208 may be as described above.

[0091] As described above, in an embodiment, the detector 240 is located between the objective lens array 241 and the sample 208. The detector 240 may face the sample 208. Alternatively, as Figure 6 shown, in an embodiment, the objective lens array 241 including a plurality of objective lenses is located between the detector 240 and the sample 208. In addition to those described herein, the detector 240 may have, for example, all the features of the embodiments previously referred to Figure 3 and 5 described.

[0092] In an embodiment, the deflector array 95 is located between the detector 240 and the objective lens array 241. In an embodiment, the deflector array 95 includes a Wien filter (or even a Wien filter array), such that the deflector array may be referred to as a beam splitter. The deflector array 95 is configured to provide a magnetic field to separate the charged particles projected onto the sample 208 from the secondary electrons from the sample 208. However, preferably, the system includes electrostatic components rather than magnetic components.

[0093] In an embodiment, the detector 240 is configured to detect signal particles by referring to the energy of charged particles (i.e., depending on the bandgap). Such a detector may be a semiconductor-based detector, such as a PIN detector or a scintillator (which is optically connected to a photon converter or a photon-to-electron converter). Such a detector 240 may be referred to as an indirect current detector. Secondary electrons emitted from the sample 208 obtain energy from the field between the electrodes. The secondary electrodes have sufficient energy once they reach the detector 240.

[0094] The control lens array 250 may be in the same module as the objective lens array 241, i.e., form an objective lens array assembly, or in one terminology, be part of the objective lens array, or may be in a separate module.

[0095] In some embodiments of any of the embodiments described and illustrated, for example, with reference to Figure 3 、 5 and 6, one or more aberration correctors are provided to reduce one or more aberrations in the sub-beams. One or more aberration correctors may be provided in any embodiment, for example, as part of a charged particle optical device, and / or as part of an optical lens array assembly and / or an evaluation system, and / or as part of an electro-optical arrangement. In an embodiment, each aberration corrector in at least a subset of the aberration correctors is positioned in or directly adjacent to a corresponding intermediate focus in the intermediate foci (e.g., in or adjacent to the intermediate image plane). The sub-beams have a minimum cross-sectional area in a focal plane such as the intermediate plane or near the focal plane. This provides more space for the aberration correctors compared to the space available elsewhere, i.e., upstream or downstream of the intermediate plane (or compared to the space available in an alternative arrangement without an intermediate image plane).

[0096] In an embodiment, the aberration corrector positioned in or directly adjacent to the intermediate focus (or intermediate image plane) includes a deflector for correcting the source 201 that appears to be at different positions for different beams. The corrector may be used to correct the macroscopic aberration caused by the source, which prevents good alignment between each sub-beam and the corresponding objective lens.

[0097] The aberration corrector can correct aberrations that prevent proper column alignment. Such aberrations may also cause misalignment between the beamlets and the corrector. For this reason, it may be desirable to additionally or alternatively position the aberration corrector at or near the converging lens 231 (e.g., each such aberration corrector is integrated with or directly adjacent to one or more of the converging lenses 231). This is desirable because, at or near the converging lens 231, the aberrations will not also cause a shift in the corresponding beamlets due to the converging lens being vertically close to or coinciding with the beam aperture. However, a challenge with positioning the corrector at or near the converging lens is that the beamlets have a relatively large cross-sectional area and a relatively small pitch at this location relative to locations further downstream. The aberration corrector can be a CMOS-based individually programmable deflector as disclosed in EP2702595A1, or a multipole deflector array as disclosed in EP2715768A2, the descriptions of the beam wave manipulators in both documents being incorporated herein by reference.

[0098] In some embodiments, each aberration corrector in at least a subset of the aberration correctors is integrated with or directly adjacent to the objective lens array 241. In embodiments, these aberration correctors reduce one or more of: field curvature; focus error; and astigmatism. Additionally or alternatively, one or more scanning deflectors (not shown) can be integrated with or directly adjacent to the objective lens array 241 for scanning the beamlets 211, 212, 213 over the sample 208. In embodiments, the scanning deflectors described in US 2010 / 0276606, which is incorporated herein by reference in its entirety, can be used.

[0099] like Figure 2 As shown (when relative to Figures 3 to 6

[0046] As described above, the projection assembly 60 is used to direct the light beam 62 onto the sample 208 to control the charge accumulated due to effects such as photoconductivity, photoelectric or thermal effects; thereby regulating the charge accumulated on the sample.

[0100] In an embodiment, the optical system 63 includes a cylindrical lens 64. The cylindrical lens 64 is configured to focus the light beam 62 more in one direction than in an orthogonal direction. The cylindrical lens increases the design freedom of the light source 61. In an embodiment, the light source 61 is configured to emit a light beam 62 having a circular cross section.

[0101] The cylindrical lens 64 need not be provided. In an alternative embodiment, another optical component capable of focusing more strongly in one direction than in another direction may be used. In an alternative embodiment, the light source is configured to emit a light beam 62 that is, for example, elliptical or rectangular. Although the dimension between the sample and the most downstream surface of the charged particle device 41 is small and the dimension of the downstream surface of the electron optical device orthogonal to the orientation of the beam path is large, this is desirable to ensure that the light beam reaches the portion of the sample that needs to be irradiated.

[0102] In an embodiment, the optical system 63 includes reflective surfaces 65, 66, such as mirrors. For example, two reflective surfaces 65, 66 may be provided. In an alternative embodiment, the optical system 63 does not reflect the light beam 62. The number and arrangement of the reflective surfaces may be selected depending on the dimensions of the volume in which the projection system 60 needs to be installed. Such reflective surfaces may be desirable to improve the arrival of the light beam 62 between the most downstream surface of the charged particle device and the sample.

[0103] The projection optical assembly 60 may exist as one or more other embodiments. In one arrangement, the path of light from the light source 61 may pass at least partially through the charged particle device 41. For example, the path of light may enter the charged particle device upstream of the objective lens array 240 and be reflected towards the sample by the reflective surface 65 within the charged particle device 41, such as through an aperture defined in a plate defining the objective lens array and other charged particle optical elements of the charged particle device. In an embodiment, the light source may be close to the source 201, such as around and / or adjacent to the source 201, such that the path of light towards the sample passes through all elements of the charged particle device 41. In another embodiment, the path of light is through an optical waveguide from the light source to the objective lens array, such as disclosed in EP 22204243.4 filed on October 27, which is incorporated herein by reference, at least with respect to the disclosure of the optical waveguide for outwardly coupling light towards the sample. Compared with that depicted and described in the reference Figure 2 The light may be outwardly coupled from a position closer to the path of the beams 211, 212, 213 to irradiate the sample. Additionally or alternatively, during operation, the light is coupled into an optical light path in a charged particle element (such as a facing element) close to (such as facing) the sample 208. The light is outwardly coupled from or through an aperture defined in the facing element.

[0104] The present invention disclosed herein can be applied to a variety of different tools or charged particle device architectures. The charged particle device includes multiple columns of multiple beams (or multiple beam devices). Each column can be a charged particle device described in any of the above embodiments or aspects, such as the charged particle device 41. As multiple columns that can be multiple devices (or multi-device arrays) (e.g., in a multi-column device trade-off), these devices can be arranged in an array, and the number of the array can be two to one hundred devices or more (or can be two to one hundred columns). The charged particle device can adopt Figure 4 the form of the depicted embodiment, which is a device including multiple charged particle devices 41 described above with reference to Figure 5 . The charged particle device preferably has an electrostatic scanning deflector array and an electrostatic collimator array. The charged particle device can optionally include a source. Note that in different arrangements, the devices in the multi-device array can adopt any suitable design, such as those shown and described with reference to Figure 3 or 6 (not shown).

[0105] Figure 7 A plan view of an element 300 is illustrated, such as an element defining an aperture array, such as an electro-optical element for interacting with charged particles, such as operating on charged particles of a primary beam for example. Such an electro-optical element can have one or more of the following characteristics: an objective lens array or a converging lens array or a part thereof, such as lens arrays 231, 241, 250; collimators 235, 271, 270, such as collimator arrays 235, 271, which can be collimated by lensing (such as lensing collimators 235, 270) and / or by deflection 271; a scanning deflector array 260, 265; an aperture-limiting array 231, 242, 252 for generating and / or shaping a charged particle beam; or a detector array 240 for detecting charged particles of the primary beam and / or charged particles from a sample 208. The element 300 is included in the charged particle device 41. In one arrangement, the element can span the entire cross-section of the charged particle device 41.

[0106] As described above, Figures 3 to 6Each of the aspects depicted includes a charged particle device 41, which includes a source 201. The source is configured to emit a respective source beam of charged particles along a respective path of a beam grid towards a sample. The beam grid includes a plurality of charged particle beams. An element 300 is configured to interact with the charged particles, such as to manipulate the charged particle beams in the beam grid of the individual source beams. The element 300 includes a beam region 70 assigned to the source beam of the source 201 from the charged particle device 41. The beam region 70 is a region on the surface of the element 300 spanned by the beam grid. One or more apertures may be defined in the element. The apertures may correspond to the beam paths of the beam grid, a group of beam paths of the beam grid, or all of the beam paths of the beam grid (i.e., the paths of the beam grid).

[0107] The element 300 may be separated from an adjacent element disposed downstream of the element 300 by a spacer 80. The element 300 and the adjacent element may be, for example, electrodes. In particular, the element 300 and the adjacent element may be a pair of electrode plates. The element and the adjacent element may include at least a part of a lens array, such as a control lens array 250 or a converging lens array 231. The spacer may provide a physical separation between the element 300 and the adjacent element in the path direction of the beam grid. The spacer may support the elements to which it is connected, such as the element 300 and the adjacent element. In an element stack (e.g., multiple elements are layered on top of each other using staggered spacers), the spacer may provide structural or mechanical rigidity to the element stack. The spacer may thermally insulate the elements (such as the element 300 and the adjacent element) from each other. The spacer may be electrically isolated, for example, electrically isolating the elements to which it is connected, such as the element 300 and the adjacent element. In different embodiments, the spacer may be conductive such that no potential difference is applied between the connected elements, for example, between the element 300 and the adjacent element; that is, the connected elements have the same potential difference relative to other elements of the charged particle device 41.

[0108] Figure 7 A spacer region 85 is illustrated. The spacer region 85 is provided between 70 and 80 and is part of the substrate of the element 300. The dimensions of the spacer region 85 may be designed to have sufficient dimensions between the beam region and the spacer and may be featureless to reduce the likelihood of an undesired discharge occurring, for example, at the surface of the spacer 80. The spacer region 85 optionally includes virtual apertures to suppress edge effects around the beam region and / or vent holes for fluid conduction, pressure control, and contamination suppression. The spacer region 85 covers the distance between the beam region 70 and the nearest spacer 80. The shortest distance between the beam region 70 and the nearest spacer 80 to that beam region 70 is desirably greater than or equal to a predetermined threshold distance, which is large enough to limit the likelihood of an undesired discharge.

[0109] Figure 7The access area 90 is illustrated, which represents an area of the charged particle device 41 for providing: service connections to one or more elements of the charged particle device 41, such as electrical connections, connections for control and data signals, connections for cooling fluid; feedthroughs; connections between service connections and feedthroughs; and access to components, for example during maintenance.

[0110] The present invention disclosed herein can be applied to various different charged particle device architectures. For example, as Figure 8 shown, the charged particle device 41 includes a plurality of sub-devices 42, where each sub-device 42 can be described in any of the above embodiments or aspects. As a plurality of devices (or, for example, a multi-device array included in a multi-device device), these devices can be arranged in an array, and the number of the array can be two to one hundred devices or more. Such a device 41 can be referred to as a multi-device 41 (or a charged particle multi-device).

[0111] The charged particle device can take the form of Figure 8 the depicted embodiment, which is a charged particle device including a plurality of sub-devices 42, and the reference numerals have the meanings described above with reference to Figure 3 description. The charged particle device preferably has an electrostatic scanning deflector array and an electrostatic collimator array. The charged particle device 41 includes a plurality of sources 201. Note that in different arrangements, the devices in the multi-device array can adopt any suitable design, such as those shown and described with reference to Figures 4 to 6 (not shown). Each source 201 is configured to emit a corresponding source beam of charged particles along a corresponding path of the beam grid towards the sample 208. The beam grid includes a plurality of charged particle beams, which can be referred to as sub-beams or beam waves.

[0112] With an arrangement having a plurality of sub-devices, such as Figure 8 the arrangement of, compared to a system including a plurality of individual charged particle devices, each having a corresponding source to provide a relative number of beam regions, the number of components can be reduced. In this way, as for example Figures 9A to 9C shown (providing a plan view of the element 300', which can have an equivalent electro-optical function to the element 300 of Figure 7 ), with an arrangement such as Figure 8 the arrangement of, there can be a plurality of beam regions, each corresponding to one of the plurality of sources. It should be noted that with Figures 9A to 9C , the common reference numerals in these different figures indicate similar features, which can have different dimensions in different embodiments (for example, beam regions having similar dimensions).

[0113] Each beam region can correspond to a different source, such as the surface of element 300’ assigned to a beam raster derived from the source. The surface areas of elements 300, 300’ assigned to the beam region and the corresponding beam raster can be greater than the surface area required for the beam raster. For example, in Figures 9A to 9C different beam rasters 70a to 70e are depicted having outer concentric boundaries that form an annulus or ring around the periphery of the corresponding beam region. This annular region desirably ensures sufficient space between adjacent beam regions to account for alignment tolerances and reduce the likelihood of interference (or crosstalk) occurring between adjacent beam rasters. For example, an annular region around or peripheral to each beam region assigned to a specific beam region. The annular region can be considered to have the beam region assigned to it; the characteristics of the annular region can be indistinguishable from the portion of the beam region actually used by the beam raster (desirably, alignment variations between different beam rasters and their corresponding beam regions enable the beam raster to project through element 300’ without creating distinguishable variations or differences between different beam rasters; that is, the alignment variations may be within the tolerances allowed by the annular regions of adjacent beam regions). The annular region can be located, for example, between the outer periphery of the beam region and the outer periphery of the active portion of the beam region through which the corresponding beam raster passes. The annular region of each beam raster can be considered part of the spacing region between the path of the beam raster and an adjacent spacer, such as the shortest distance between the periphery of the active portion of the beam raster and the nearest surface of the spacer; although the characteristics of the annular region within the spacing region can have the characteristics of the beam raster rather than the rest of the spacing region.

[0114] For example, Figure 9A three beam regions 70a to 70c that can be equally spaced apart are depicted; Figure 9B four beam regions 70a to 70d that can be at least equally spaced apart from adjacent beam regions are depicted; Figure 9C six beam regions 70a to 70f are depicted, where the beam regions are equally spaced apart from adjacent beam regions. As needed, there can be as many different beam regions. Despite there being more beam regions, some features and components of element 300’ can be maintained or increased to a lesser extent than the number of beam regions. That is, if multiple beam regions are implemented through individual charged particle devices 41 with separate elements 300’, the number of components and features is less than expected.

[0115] Reducing or preventing the number of such component features corresponding to the number of beam regions (e.g., reducing the number of components and features compared to what is expected if separate elements with different beam raster paths are used) can provide multiple beam regions in a more compact area. The access area required to operate and maintain such multiple devices can desirably be reduced. (This assumes that the size of the beam regions is the same as when providing separate elements 300 or at least access areas 90 for different beam regions). For example, Figure 7 the access area 90 corresponds to a single beam region 70, while inFigures 9A to 9C In the arrangement, for a plurality of beam regions, such as Figure 9A for the three beam regions 70a to 70c of Figure 7 there is a single access region 90'. In Figure 9A the same arrangement where the beam region 70 of Figure 9A is the same as the beam region 80' of Figure 7 (although this is not necessarily the case), if the access regions 90' are not the same regions, the size of the access region 90' does not increase significantly (compared with the access region 90 of

[0116] In an arrangement including a plurality of beam regions 70a to 70c, such as Figure 9A each of the beam regions 70a, 70b, 70c can have the same size or area as the corresponding beam region 70 of an arrangement such as Figure 7 (where there is only one beam region 70). Alternatively, the sizes or areas of the beam regions 70a to 70c of an arrangement with a plurality of beam regions can be different from the corresponding beam region 70 of an arrangement such as Figure 7 (where there is only one beam region 70). In addition, the plurality of beam regions 70a to 70c can include beam regions of different sizes. In other words, there can be more than one size or area of beam region within the same charged particle device 41. It is desirable for all of the beam regions 70a to 70c in the plurality of beam regions to have the same size, or to cover the same region on the element 300'.

[0117] In one arrangement, the more beam regions there are in the element 300', the proportionally smaller the access region 90' for each beam region may be. In this way, compared with the sample region that the device can evaluate simultaneously, the total size of the access region 90' can be reduced, thereby increasing the production rate. That is, for an arrangement with a plurality of beam regions, such as described and depicted in reference Figures 9A to 9C the proportion of the element area of the access region 90' assigned to the multi-device is smaller; desirably, the proportional size of the access region 90' decreases as the number of beam regions increases (even though the size of the element 300' (e.g., across multiple devices) may increase as the number of beam regions increases. Therefore, compared with a single beam region 70, the proportional size of the element 300' assigned to the beam region and used to operate the beam of the beam grid of the multi-device is larger when there are a plurality of beam regions, and can increase, for example, as the number of beam regions increases.

[0118] As mentioned, the size of the evaluation system (e.g., the area (or footprint) required to accommodate such an evaluation system in a production facility) is typically determined by the area required for the platform operation of scanning a sample by the charged particle device of the evaluation system. The more charged particle devices in the evaluation system, the larger its area (or footprint). Since the available footprint for such an evaluation system in the production facility of a chip manufacturing plant is limited, the number of charged particle devices that can be present in an evaluation system having an array of charged particle devices for scanning samples of typical size may be limited. Therefore, by implementing a more dense beam area arrangement within the device 41, the present invention is capable of increasing the sample production amount of such an evaluation system.

[0119] It should be noted that, so far, this discussion has assumed that the effects of all elements of the multi-device are the same. However, the beam areas required for elements at different positions along the path of charged particles from the source 201 to the sample 208 or at least the collimator 235 (270, 271) increase in size with the distance from the source. The source beam and the beam of the beam grid (when present upstream of the collimator) diverge. Between the collimators 235, 270, 271 and the sample, different beams are substantially collimated. Between the surface of the device 41 facing the sample and the collimator, the beam areas between different (e.g., adjacent) elements 300 may be similar, if not identical. Such elements can be electro-optical elements, such as lens electrodes of the collimators 235, 270, 271, the detector array 240, the objective lens array 241, and the control lens array 250, the scanning deflectors 260, 265, and the beam limiting aperture arrays 242, 252. Elements between the source 201 and the collimators 235, 270 may have a beam area smaller than that of the collimator in the same charged particle device 41. Such elements 300 that can be between the collimator and the source can be: the converging lens array 231 and its constituent or associated beam limiting aperture array, and any other element that can be positioned in the diverging path of charged particles from the source 201, such as a corrector.

[0120] Unlike Figure 7 the arrangement of Figures 9A to 9C in the arrangement of Figure 8 the element 300' includes a plurality of beam areas, where each beam area is assigned to a separate source beam from a separate source among a plurality of sources 201, such as shown in the arrangement of

[0121] As discussed above, although such as Figure 8Each beam region in the multi-device 41 shown (i.e., in the device 41 having multiple sources 201) corresponds to a separate beam grid corresponding to one particular source 201 of the multiple sources 201, but some other components of the device 41 are desirably shared between different beam regions. For example, the device may include a spacer 80' disposed between the element 300' and an adjacent element. The spacer may include a support member. The support member is desirably disposed between the element 300' and the adjacent element for supporting the element and / or the adjacent element. As for example Figure 9A shown, the spacer 80' has at least one aperture that is positioned to correspond to the positions of at least two beam regions, such as a single aperture surrounding all beam regions 70a, 70b, 70c (e.g., multiple beam regions). In Figure 9A the example of, the aperture defined by the spacer 80' is positioned to correspond to (e.g., circumscribe or enclose) three beam regions 70a to 70c. In an alternative arrangement, the aperture defined by the spacer is positioned to correspond to (e.g., enclose) two to six beam regions, for example.

[0122] As for example ​ shown, the spacer may include an external support member 81 that has an aperture positioned to correspond to the multiple beam regions 70a to 70d. As ​ shown, the aperture of the external support member 81 may be positioned to correspond to or enclose four beam regions, such as a single aperture surrounding all beam regions 70a, 70b, 70c, 70d (e.g., multiple beam regions). In other words, the aperture of the spacer may enclose the multiple beam grids emitted by multiple (e.g., four) sources 201. In an alternative arrangement, the external support member 81 may have an aperture that is positioned to correspond to or enclose two or more beam regions, such as two to six beam regions.

[0123] ​ The external support member 81 defines a circular aperture. Alternatively, the aperture defined by the external support member 81 may not be circular, for example, the aperture may be rectangular, oval, hexagonal, or elliptical, or may be shaped to correspond to the beam grid surrounded by the external support member 81.

[0124] The multiple beam regions are optionally arranged in a two-dimensional array. Desirably, the two-dimensional array has a pattern. For example, as ​ shown, the two-dimensional array may include at least 2 rows of parallel beam regions, where each row includes at least 2 beam regions. Alternatively, as for example ​As shown, a plurality of beam regions may have a pattern including, for example, an annulus around the central position of the beam region. The plurality of beam regions may include at least one annulus of the beam region. For example, at least one annulus of the ring region may be the ring 71 of the beam region. The pattern may define that each beam region 70b is equidistantly spaced from its adjacent or neighboring beam regions 70a, 70c, etc., for example, in the annulus. Hereafter, the term ring is used to describe the arrangement of beam regions such as ​ as depicted. However, in an alternative arrangement, the beam regions may be arranged surrounding a central point. The arrangement of the beam regions may be circular and may form an annulus, particularly a ring, or may be non-circular, such as ​ the three beam regions 70a to 70c.

[0125] In ​ the arrangement, the ring 71 of the beam region may be positioned around the central position of the plurality of beam regions, for example, in an annulus (such as a two-dimensional ring) around the central position. The central position may be set at the midpoint between the plurality of beam regions. For example, the central position may be equidistant from each of the plurality of beam regions surrounded by the outer support 81. The beam regions may be equidistantly spaced from their adjacent or neighboring beam regions 70a, 70c, etc., for example, in the annulus. In other words, in ​ and ​ the arrangement, the two-dimensional array includes beam regions arranged around an intermediate region. In these examples, the intermediate region is located at the central position of the plurality of beam regions. For example, in ​ the arrangement, the two-dimensional array is an annulus of beam regions that forms the ring 71 of the beam region.

[0126] As for example ​ and ​ shown, the spacer optionally includes an internal support 82 disposed between the element 300’ and the adjacent element for supporting the element and / or the adjacent element. The periphery of the internal support 82 is surrounded by more than two beam regions. In ​ the depicted embodiment, the internal support 82 is surrounded by four beam regions. In ​ the depicted embodiment, the internal support 82 is surrounded by six beam regions 70a to 70f. In ​ and ​ the arrangement, the internal support 82 may be positioned at the central position at the midpoint of the plurality of beam regions. There may be more than one internal support, and one internal support may be located at the central position; in different arrangements, all central supports are positioned away from the central position, desirably within the outer support 81.

[0127] The internal support 82 desirably provides sufficient support for the element 300' such that the beam regions (or regions of adjacent elements defining adjacent beam regions) can be spaced apart such that the diameter of the aperture defined by the external support 81 is greater than ​ the diameter of the arrangement of. In ​ the depicted arrangement, there is a single support, namely, the external support 81. Thus, the external support 81 supports the element 300' and / or the adjacent elements such that the gap between the element and the adjacent elements is maintained above, for example, a threshold distance; that is, the space between the element and the adjacent elements (e.g., defined by the gap) is maintained above or at the threshold distance, for example, in the intermediate region of the space, the element, and / or the adjacent elements. Thus, in the intermediate region where there may be a risk of discharge, the gap does not decrease excessively. Using the reference ​ depicted and described arrangement, the diameter of the aperture defined by the external support 81 can have a threshold diameter that defines the maximum acceptable diameter. This may mean that the diameter of the aperture cannot exceed the threshold diameter and the element 300' exceeds the threshold diameter; otherwise, the element and the adjacent elements (e.g., at the intermediate region) will not have sufficient support risk and the discharge risk increases. Thus, compared to the beam regions 70a to 70d of the arrangement of ​ , the beam regions 70a to 70c in the arrangement of ​ are spaced closely together. In ​ the arrangement, the internal support 82 provides support for the element 300' in the intermediate region, for example, between the surrounding beam regions, such as equidistant from the surrounding beam regions. Thus, for example, the diameter of the aperture of the external support 81 surrounding four beam regions (as shown and described in reference ​ ) can be greater than the aperture of the spacer surrounding fewer beam regions (such as having three beam regions, as depicted in ​ ).

[0128] Optionally, in an alternative arrangement, one or more apertures can be defined in the internal support. Such apertures can be arranged to correspond to or surround one or more beam regions. For example, the plurality of beam regions can include, for example, a central beam region relative to the respective apertures provided in the intermediate region of the element. The central beam region is desirably provided at a central position. The central beam region is optionally surrounded by the internal support. As described for the external support 81 shown and described in reference ​ , 9A to 9C, such an internal support can have the same features.

[0129] In an arrangement of a multi-device 41 including the element 300', such as in reference ​As shown and described, there can be multiple sub-devices 42. The number of sub-devices 42 in the charged particle multi-device 41 can be used to provide coverage of a number of charged particle beams on the sample surface, such as simultaneously scanning a sample, such as a sample with industrial standard dimensions, such as 300 mm in diameter. Compared with using multiple charged particle devices 41 each having only a single source and a single beam area, for example instead of a source array with multiple beam areas, the time required for such a multi-device 41 can be reduced. Currently, the beam current that a single source can generate is limited. Using multiple sources can effectively increase the beam current without increasing the beam current of each source. Further, compared with scanning a sample by a charged particle device 41 having only one source, the sample area scanned per unit time by the multi-source 41 will be larger; that is, the surface area of a standard sample will be scanned in a shorter time. The production volume of the multi-device 41 will be greater than that of a known device having a single source. Therefore, each device 41 including multiple beam areas (such as a multi-device) can reduce costs by reducing the total number of devices used for each sample. Further, making the density of the beam areas generated by the multi-source greater than the known designs of multi-devices enables such a multi-device to have a larger proportion of its cross-section as beam areas; scanning the sample surface with such a multi-device may be faster, thus obtaining a greater production volume. Arranging the multiple beam areas of each multi-device 41 at a greater density can further reduce the scanning time required for each sample, such as the cost of goods.

[0130] Inside the inner support member can be one or more other inner support members, which can have the same features as the inner support member shown and described. ​ The outer support member 81, the inner support member 82, and the other inner support members can be referred to as a support arrangement, such as a concentric support arrangement. Such a concentric support arrangement can have as many support elements as needed; for example, at least two concentric elements with a common axis can be present at the central position. However, it is desirable that the support arrangement has several support elements, for example to optimize (desirably maximize) the ratio of the beam area to the element.

[0131] In ​ Another alternative exemplary arrangement is illustrated. ​ The arrangement of ​ includes a plurality of beam areas 70”, spacers, and an access area 90”. Similar to the arrangement of ​ There is at least one annulus of beam areas, which is depicted as a beam area ring. ​ The arrangement of

[0132] ​The arrangement also includes an outer ring 73 of the beam region. The outer ring 73 of the beam region surrounds the inner ring 72 of the beam region. The outer ring 73 of the beam region is positioned concentrically around the inner ring 72 of the beam region. In ​ the arrangement, the outer ring of the beam region includes nineteen beam regions. In an alternative arrangement, the outer ring may include any number of beam regions, such as from six to twenty beam regions, for example more than the number of beam regions within the inner ring 72. Additionally, the alternative arrangement may optionally include multiple rings of beam regions, such as one or more additional rings. The additional rings may be provided concentrically surrounding the outer ring such that the outer ring may be positioned between the inner ring and the additional rings. For example, in one arrangement, there may be up to four rings, including an inner ring having up to 6 beam regions: the outer ring may have up to 20 beam regions; there may be two additional rings having up to 33 and up to 46 beam regions respectively. The multiple rings may be provided on a sample having a diameter of 300 mm. The charged particle device 41 (or multiple devices) may have more than 100 sources 201 (such as up to 105 sources 201); thus there may be, for example, more than 100 sub-devices 42. Different sources 201 may emit charged particles that impinge on a sample of a beam grid having corresponding beam regions 75; note that in portions of the sub-device 42 having divergent charged particles, the beam regions may be smaller. Multiple beam regions of beam grids of different sub-devices 42 may be provided on a single sample, for example the sub-devices may be configured to scan the sample simultaneously as desired.

[0133] In ​ the arrangement, the spacer further includes an intermediate support 83 disposed between the element and the adjacent element for supporting the element and / or the adjacent element. In particular, in ​ the arrangement, the intermediate support 83 is configured to surround the inner ring 72 of the beam region. The intermediate support 83 is surrounded by the outer ring 73 of the beam region. ​ the arrangement includes an external support 84 configured to surround the outer ring 73 of the beam region. In an alternative arrangement, the external support may not be included as the intermediate support may provide sufficient support for the element and the adjacent element such that the element and the adjacent element. Additionally, as shown for example in ​ the spacer may include an internal support 82 which is desirably disposed in an intermediate region and more desirably disposed at a central location.

[0134] In ​In the arrangement, the intermediate support 83 defines one of the at least one aperture defined by the spacer. The intermediate support 83 is positioned to correspond to the inner ring 72 of the beam region 70”. In an alternative arrangement, the intermediate support may have a continuous surface without apertures. The intermediate support may be positioned between at least one beam region of the inner ring 72 of the beam region and at least one beam region of the outer ring 73 of the beam region. The intermediate support may include a plurality of discrete support structures disposed around the inner ring of the beam region. In this way, the intermediate support provides support for the components between the inner ring 72 and the outer ring 73.

[0135] The intermediate support is optionally positioned between two adjacent beam regions, such as equidistant between two or more beam regions. Desirably, the position of the intermediate support corresponds to the intermediate region. Desirably, the intermediate support surrounds one or more beam regions. The intermediate support may define one or more apertures. For example, the intermediate support may define a plurality of apertures. Each aperture of the intermediate support may correspond to or surround at least one beam region. Desirably, each aperture of the intermediate support may surround two or more adjacent beam regions.

[0136] Desirably, the component is configured to be positioned such that the aperture array is arranged along the path of the beam grid. The components 300, 300’ may be, for example, electrodes of a lens array. Desirably, the electrode is an electrode plate. The lens array optionally includes adjacent components and spacers.

[0137] ​ The spacers 80’, 81, 83 in 10 are shown as continuous and surround a plurality of beam regions. The spacer may be a plurality of discrete support structures disposed at positions around the plurality of beam regions, rather than continuous.

[0138] Such as ​ and ​ Each arrangement of the beam regions shown corresponds to a different charged particle sub-device 42 having a different number of sources 201. The number of beam regions may correspond to the number of sub-devices 42. In particular, the charged particle device 41 associated with ​ includes three sources 201; while the charged particle device 41 associated with ​ includes four sources 201; the charged particle device 41 associated with ​ includes six sources 201. The charged particle device 41 associated with ​ includes 25 sources 201.

[0139] A dense arrangement of beam regions in the multi-device 41 enables, for example, multiple multi-devices 41 of the same design to be scanned over a sample. This arrangement can increase the production rate. For example, having ​Up to seven (7) charged particle devices 41 with the arrangement of the multiple beam regions shown can be arranged facing a single sample having a standard diameter of, for example, 300 mm. Desirably, the charged particle devices 41 are configured such that the multiple beams of the beam grid are configured to scan the sample simultaneously. In this way, a total of up to twenty-one (21) beam regions can be provided simultaneously on the same sample.

[0140] In one arrangement, with reference ​ Up to seven (7) charged particle devices 41 with the arrangement of the multiple beam regions shown and described can be arranged facing a single sample with a diameter of 300 mm; desirably, the charged particle devices 41 are configured such that the multiple beams of the beam grid are configured to scan the sample simultaneously. In this way, a total of up to twenty-eight (28) beam regions can be provided simultaneously on the same sample. With ​ Up to seven (7) charged particle devices 41 with the beam region arrangement shown can be arranged facing a single sample with a diameter of 300 mm; desirably, the charged particle devices 41 are configured such that the multiple beams of the beam grid are configured to scan the sample simultaneously. In this way, a total of up to 42 beam regions can be provided simultaneously on the same sample.

[0141] Similar arrangements can be applied to reference ​ and 10 the multi-device 41 shown and described.

[0142] Elements 300, 300' and any corresponding adjacent elements (or facing adjacent elements) are all included in the lens array. The lens array can be a converging lens array, which can correspond to, for example, the array of converging lenses 231 described above with reference ​ described. The charged particle device 41 can include multiple converging lens arrays, each converging lens array including the element 300' described above with reference to FIGS. 9 and ​ described. One or more converging lens arrays are desirably configured to generate the multiple beams of the beam grid from the respective source beams. Alternatively or additionally, the lens array can be an objective lens array, which can correspond to, for example, the objective lens array 241 described above with reference ​ described. The charged particle device 41 can include multiple objective lens arrays, each objective lens array including the element 300' described above with reference to FIGS. 9 and ​ described. One or more objective lens arrays are desirably configured to operate on the multiple beams of the beam grid.

[0143] An apparatus may include one or more condenser lens arrays and one or more objective lens arrays. Each of the lens arrays may include element 300’. Such an objective lens array is desirably disposed downstream of the condenser lens array. In this way, one or more condenser lens arrays are disposed at an upstream position relative to one or more objective lens arrays. One or more objective lens arrays are disposed at a downstream position relative to one or more condenser lens arrays.

[0144] At least one of the one or more condenser lens arrays desirably has more than one beam region among a plurality of beam regions. For example, the charged particle device 41 may include a single condenser lens array. Thus, a plurality of beam grids may form beam regions on the same condenser lens array. In an alternative arrangement, there may be a plurality of condenser lens arrays, for example, each condenser lens array includes a different element 300’, and each condenser lens array may be arranged such that a plurality of beam regions correspond to each condenser lens array.

[0145] Similar to the one or more condenser lens arrays, the charged particle device 41 (or multi-device 41) may additionally or alternatively include one or more objective lens arrays. At least one of the one or more objective lens arrays desirably has more than one beam region among a plurality of beam regions. For example, the charged particle device 41 may include a single objective lens array. Thus, a plurality of beam grids may form beam regions on the same objective lens array. In an alternative arrangement, there may be a plurality of objective lens arrays, and each objective lens array may be arranged such that a plurality of beam regions correspond to each objective lens array.

[0146] The one or more lens arrays may optionally include a greater number of condenser lens arrays than objective lens arrays. Desirably, on average, each objective lens array has more beam regions than each condenser lens array. For example, there may be a plurality of condenser lens arrays and there may be a single objective lens array. The number of condenser lens arrays may optionally correspond to the number of sources. Alternatively, the number of beam regions of each objective lens array may be the same as the number of beam regions of each condenser lens array. With this arrangement, desirably, each objective lens array has the same number of beam regions as the corresponding condenser lens array assigned to the same source beam. For example, each objective lens array may be disposed directly downstream of the corresponding condenser lens array.

[0147] In at least one of the one or more lens arrays, an aperture array defines at least one pattern. The pattern may exist as a patterned array, such as a two-dimensional aperture array in one or more elements 300' included in the one or more lens arrays. The pattern of apertures may have apertures positioned at least on the beam regions provided by the one or more elements. For example, in at least one lens array, the aperture array may define a single continuous pattern, such as a continuous pattern of a two-dimensional aperture array. In particular, in at least one of the one or more lens arrays, the distance between the apertures of the aperture array within two different adjacent beam regions may be the same as the distance between the adjacent apertures of the two different beam regions. In this way, there may be no discontinuity in the pattern between different beam regions of the lens array; that is, the pattern of apertures defining the beam regions may be continuous, such as between and including the beam regions.

[0148] Alternatively, there may be multiple patterns. The multiple patterns may be multiple occurrences of the same pattern. Alternatively, the multiple patterns may include two or more different patterns that are different from each other. The multiple patterns may be discontinuous from each other such that the distance between adjacent apertures within the same pattern is less than the distance between the apertures of adjacent patterns. Each pattern of the multiple patterns may correspond to a respective beam region. For example, in at least one of the one or more lens arrays, the distance between adjacent apertures from different adjacent beam regions may be different from the distance between the apertures within the respective beam regions. In particular, in at least one of the one or more lens arrays, the distance between the apertures of the aperture array within two different adjacent beam regions may be different from the distance between the adjacent apertures of the two different beam regions. Alternatively, instead of or in addition to the patterns being different due to being far apart from each other, the patterns may be different due to the arrangement of the apertures. Desirably, the array of beam regions of the discontinuous patterns included in the aperture array of one or more converging lens arrays is greater in number than the discontinuous array of the aperture array of the objective lens array.

[0149] One or more lens arrays desirably include a plurality of lens arrays, which include at least two sets of lens arrays. Each set of lens arrays includes one or more lens arrays of the plurality of lens arrays. For example, the plurality of lens arrays may include one or more converging lens arrays, and the one or more converging lens arrays may form a set of lens arrays. The plurality of lens arrays may include one or more objective lens arrays, and the one or more objective lens arrays may form another set of lens arrays. This also applies to collimating lens arrays and / or control lens arrays.

[0150] Desirably, each set of lens arrays is configured to be controlled individually. In particular, at least one set of lens arrays may be configured to be actuated relative to at least another set of lens arrays in at least one degree of freedom. Desirably, at least one of the one or more lens arrays is configured to be actuated in up to six degrees of freedom. This will desirably enable the groups of lens arrays to be aligned relative to each other.

[0151] At least one set of lens arrays includes at least one lens array having a plurality of beam regions. The plurality of beam regions optionally corresponds to a ring of beam regions, such as ​ the inner ring 72 of the arrangement of. Another set of lenses may include at least one lens array having a plurality of beam regions corresponding to another ring of beam regions (such as ​ the outer ring 73 of the arrangement of). In this way, it may be possible to independently align different lens arrays corresponding to different rings of beam regions. In this way, actuators configured to actuate the lens arrays can be shared between groups of lens arrays. Alternatively, each lens array can be provided with its own actuator such that each lens array is individually controllable; however, this arrangement may be more complex and require a larger access area compared to an arrangement where only each group of lens arrays has a corresponding actuator (such as a single actuator).

[0152] As referred to above with reference to FIGS. 9 and ​ described, for example, elements 300' of spacers and / or lens arrays including charged particle devices 41 (or multi-devices 41) can be shared between multiple sources 201, rather than each source 201 being associated with a dedicated element 300' (such as a spacer and / or lens array that only interacts with the beam grid of the corresponding source 201). That is, some (if not all) of the sources can share the multi-device 41. Such elements can be shared between one or more of the plurality of sub-devices 42 of the multi-device 41; each source 201 can be associated with a different sub-device 42. In addition, in addition to or as an alternative to sharing elements 300', spacers and / or lens arrays between multiple sources of charged particle devices, other components of the multi-device 41 can be shared.

[0153] ​ A side view (e.g., a cross-section along the direction of the beam path or the electron optical axis) of a charged particle device including a charged particle device 41 (or multi-device 41) is provided. As an exemplary arrangement, ​ the charged particle device 41 of provides an arrangement of four beam regions arranged in two rows of two beam regions, similar to ​ the beam region arrangement depicted. ​ the charged particle device 41 of includes a plurality of charged particle beam sources 201. ​The charged particle device 41 includes four sources 201 (two of which are visible), a collimator 235, a converging lens array 231, and an objective lens array 241. The collimator is configured to collimate a beam grid of beams from the diverging beam array from the converging lens array 231, for example as a collimated beam towards the sample. As described above, with reference to ​ , the objective lens array 231 and / or the objective lens array 241 can be formed by one or more elements 300’. Further, the detector 240 (which may be associated with the depicted objective lens array 241), the collimator array 235, the control lens array (which may be associated with the objective lens array, the scanning deflector array 235, and any other elements such as a corrector array) can each respectively include one or more elements 300’.

[0154] As ​ shown by the arrows 601, 602 in ​ , one or more of the collimator 235, the converging lens array 231, and the objective lens array 241 can be actuated in one or more directions. In principle, any element or charged particle device including a plurality of elements 300, 300’ can be actuated in one or more directions. For example, one or more of the collimator 235, the converging lens array 231, and the objective lens array 241 can be actuated in one or more translational directions and / or one or more rotational directions. In particular, one or more of the collimator 235, the converging lens array 231, and the objective lens array 241 can be actuated in ​ the Z direction 602 of ​ , where the Z direction can correspond to the flow direction of charged particles from the source 201 to the sample, and this direction can be the vertical direction. Additionally or alternatively, one or more of the collimator 235, the converging lens array 231, and the objective lens array 241 can be actuated in ​ the X direction 601 of

[0155] , where the X direction can be a lateral direction orthogonal to the Z direction, and the Z direction can be the horizontal direction. Additionally or alternatively, one or more of the collimator 235, the converging lens array 231, and the objective lens array 241 can be actuated in the Y direction, and the Y direction is a lateral (possibly horizontal) direction orthogonal to the X direction and the Z direction. Different electron optical devices can be actuated to rotate about any different axial directions of the reference frame, for example about the X, Y, and / or Z directions.

[0155] In addition, one or more elements 300' may form a collimator 235. The collimator 235 is desirably configured to operate on beams associated with different beam regions and / or beam grids. In other words, the collimator 235 may be positioned such that the collimator 235 is in the path of the beam grid from the plurality of sources 201. Similarly, the element 300' and / or adjacent elements may include a detector array such that the elements associated with the detector array have a plurality of beam regions. The detector array desirably includes detector elements associated with each aperture. The detector array is desirably configured such that the detector elements are positioned, for example, close to the objective lens array. In an embodiment, the detector array is desirably configured such that the detector elements are positioned facing the sample position where the sample is placed during use.

[0156] ​ The charged particle device further includes a cooling conduit 402 configured to thermally condition the lens array. The cooling conduit may be a path or conduit for a coolant (such as a fluid that can be thermally conditioned to have a stable temperature, such as water). The coolant may have a high heat capacity, enabling efficient thermal conditioning. In an alternative arrangement, one or more cooling conduits may be provided to thermally condition any element and / or adjacent element in the charged particle device. With this arrangement, the cooling conduit is desirably in contact with the element and / or adjacent element. For example, the cooling conduit may be provided along the surface of the element, such as away from the beam region, and the element and / or adjacent element may be composed of a material with a high heat capacity. Desirably, the cooling conduit includes at least one path between different beam regions.

[0157] The charged particle device 41 may be provided in a vacuum chamber. The charged particle device and the vacuum chamber may form components of a charged particle equipment. In particular, the charged particle device (such as the multi-device 41) is desirably fully accommodated in the vacuum chamber. In this way, a plurality of sub-devices 42 may be provided in the same common vacuum chamber, for example, continuous walls 500, such as surrounding the charged particle device 41 to maintain a negative pressure in the vacuum chamber. In one arrangement, the vacuum chamber may include an actuating platform and optionally a support 209 for supporting the sample 208. A vacuum system including a vacuum pump may be used to maintain the vacuum in the vacuum chamber. A vacuum port 406 may be provided through the wall 500 of the vacuum chamber. The vacuum port may be connected to the vacuum pump of the vacuum system.

[0158] This may be a simpler and more efficient arrangement than an alternative arrangement where each device has a dedicated single source and vacuum chamber. The common or shared vacuum chamber optionally includes at least one cooling port 403, such as ​As shown. Although three are depicted, there can be more or less as needed, for example one. The device can include a plurality of vacuum sub-chambers, desirably with each source 201 being accommodated within a respective vacuum sub-chamber. The cooling ports can be shared between different sub-chambers such that the sub-chambers can be efficiently cooled and the device does not become overly complex. The cooling port 403 can be a feedthrough through the vacuum chamber wall for a cooling conduit 402 to pass through, or a fluid supply for a cooling conduit within the chamber, with a low risk to the integrity of the vacuum chamber.

[0159] Such as for example ​ As shown, for example, in ​ , the charged particle device 41 can also include a shield 405 configured to extend at least partially between the paths of different beam grids. As ​ shown, the shield 405 can be disposed between the paths of two or more beam grids such that the beam paths of two or more beam grids share the shield 405. In this way, the shield within the device is efficiently utilized among different beam grids associated with corresponding sources 201. In an alternative arrangement, the shield can extend along the grid path where the beam regions have a discontinuous pattern.

[0160] Such as for example ​ As shown, for example, in ​ , the source 201 includes an emitter, and the device also includes a shield 405 at least between the emitters of different sources (e.g., between different sources 201).

[0161] In the charged particle device 41 described above with reference to ​ ​ , the voltage source 401 can be configured to apply a potential to an element and / or an adjacent element. The applied potential can be any potential within the operating range of the charged particle multi-device. For example, the voltage source can connect the element to ground. For example, desirably, the voltage source applies a potential to different sources, such as a ground potential or a potential elevated to a different height relative to the sample. As ​ shown, the voltage can be supplied by the voltage source 401 to the source 201 in order to emit charged particles for generating different beam grids for operation of different beam regions of the element.

[0162] The voltage source can apply a potential difference between an element and an adjacent element. In this way, a potential difference can be applied between adjacent beam regions of different elements (e.g., an element and an adjacent element) to supply a voltage of elevated potential to one or more elements of the device 41. The voltage source 401 can apply a potential to one or more elements of the lens array, such as the converging lens array 231 and / or the objective lens array 241. A voltage source 401 can be provided to operate such elements associated with multiple beam regions.

[0163] A charged particle device may include electronics associated with an element and / or an adjacent element. Each element and / or adjacent element and its corresponding electronics are desirably associated with two or more beam regions. For example, the element and / or another element may include an electrode array configured to be controlled by the electronics. In an arrangement where at least one of the element and the adjacent element is a detector, the electronics may additionally have the function of receiving, processing a directional signal from the detector, and / or sending it to an external process of the charged particle device or an evaluation system. All or part of the electronics are optionally provided at a location remote from the element and / or adjacent element. For example, the electronics may be provided outside the vacuum chamber. Alternatively or additionally, all or part of the electronics may be included on or near the element and / or adjacent element.

[0164] In the chamber wall, there may be one or more feedthroughs such that services such as power (such as electricity), signals (optical and / or electronic), and coolant can pass through the chamber wall while maintaining the vacuum inside the vacuum chamber. The charged particle device may also include such a feedthrough 404 configured for an electrical connection of a voltage source 401 to pass through to apply a potential such as an elevated potential to one or more elements of the device 41. Thus, the use of the feedthrough is more efficient compared to an alternative arrangement where different feedthroughs are associated with individual beam regions of different elements 300' of a corresponding single source.

[0165] Similarly, the charged particle device may also include a feedthrough 404 configured to send a control signal to the device 41 and receive a detection signal from the device 41. For example, the feedthrough 404 may be configured for a signal conductor to pass through to send in and out of the vacuum chamber, for example, together with one or more elements of the charged particle multi-device 41. The feedthrough 404 may be the same as the feedthrough for supplying voltage or may be a different additional feedthrough. The feedthrough 404 (which may be one feedthrough for all sources or one or more feedthroughs for different sources or groups of sources respectively) may be configured for an electrical connection to be transferred from the voltage source 401 to the source 201 (such as a transmitter).

[0166] The same feedthrough 404 can be used to transfer control signals, detection signals, and / or power through the wall 500 of the vacuum chamber, e.g., to set the potential of a source and / or component. Thus, one or more cooling ports 403 through the vacuum chamber wall 500 are effectively feedthroughs. In one arrangement, cooling conduits 402 are included within the same feedthroughs 404, 403 for control signals, detection, and / or power. Although having separate feedthroughs for different functions can assist with the layout within the vacuum chamber and can help simplify the layout of service lines (e.g., cables, optical fibers, and tubes) within the chamber, which may help maintain the vacuum chamber at a desired small size, it may be preferred to concentrate (or combine) functions into a small number of feedthroughs, preferably one. Fewer feedthroughs may help reduce the risk of a vacuum breach. A feedthrough with such combined functionality suitable for service lines (e.g., cables, wires, ducts, and other features for sending electrical signals such as PCBs) is shown and described in WO2018121969, which claims a priority date of December 27, 2016, and is incorporated herein by reference at least in terms of the features of the feedthrough and the manner of feeding through the service lines.

[0167] The following items are provided:

[0168] Item 1. A charged particle device for projecting multiple charged particle beams towards a sample, the device comprising: a plurality of sources configured to emit respective source beams of charged particles along respective paths of a beam grid, the beam grid comprising a plurality of charged particle beams; one or more elements, wherein an aperture array is respectively defined that includes a plurality of beam regions assigned to individual source beams, and wherein the one or more elements are configured to operate on the charged particle beams in the beam grid of the individual source beams; wherein each element is separated from an adjacent element by a spacer having at least one aperture positioned to correspond to the positions of at least two beam regions.

[0169] Item 2. The device according to Item 1, wherein the one or more elements are configured to be positioned such that the aperture array is arranged along the path of the beam grid.

[0170] Item 3. The device according to Item 1 or 2, wherein each beam region corresponds to an individual beam grid of one of the source beams in the individual source beams.

[0171] Item 4. The device according to any of the preceding items, wherein the element is an electrode of a lens array, desirably wherein the electrode is an electrode plate, desirably wherein the lens array includes adjacent elements and spacers.

[0172] Item 5. The device according to any of the preceding items, wherein the spacer includes an external support provided between adjacent elements to support the adjacent elements.

[0173] Clause 6. The device according to Clause 5, wherein the outer support defines at least one aperture, desirably wherein the aperture is positioned to correspond to the positions of the plurality of beam regions, desirably wherein the outer support is positioned to surround the plurality of beam regions.

[0174] Clause 7. The device according to any of the preceding clauses, wherein the plurality of beam regions are arranged in a two-dimensional array desirably having a pattern, the two-dimensional array desirably including at least 2 rows of parallel beam regions, wherein each row includes at least 2 beam regions.

[0175] Clause 8. The device according to Clause 7, wherein the plurality of beam regions include at least one ring of beam regions arranged in a two-dimensional ring around a central position at the midpoint of the plurality of beam regions, desirably at least one ring of beam regions includes up to 4 rings of beam regions.

[0176] Clause 9. The device according to Clause 7, wherein the two-dimensional array includes beam regions arranged around an intermediate region of the plurality of beam regions, desirably the intermediate region is at the central position, desirably the two-dimensional array is annular, such as an annulus of beam regions, desirably the annulus forms at least one ring.

[0177] Clause 10. The device according to Clause 8 or 9, wherein at least one ring of beam regions includes an inner ring of beam regions arranged adjacent to the central position, desirably wherein the inner ring of beam regions includes up to 6 beam regions.

[0178] Clause 11. The device according to Clause 10, wherein at least one ring of beam regions includes an outer ring of beam regions, wherein the outer ring of beam regions surrounds the inner ring of beam regions, desirably wherein the outer ring of beam regions is positioned concentrically around the inner ring of beam regions, desirably wherein the outer ring of beam regions includes up to 20 beam regions.

[0179] Clause 12. The device according to any of the preceding clauses, wherein the spacer includes an intermediate support disposed between adjacent elements to support the adjacent elements, wherein the intermediate support is positioned between two adjacent beam regions, for example equidistant between two or more beam regions, desirably the position of the intermediate support corresponds to the intermediate region, desirably for example the intermediate support surrounds one or more beam regions and is positioned around the intermediate region, for example a plurality of apertures are defined in the spacer, and the intermediate support may define one or more apertures through the support.

[0180] Clause 13. The device according to Clause 11, wherein the spacer includes an intermediate support disposed between adjacent elements to support the adjacent elements, wherein the intermediate support is positioned between at least one beam region in the inner ring of beam regions and at least one beam region in the outer ring of beam regions, desirably wherein the intermediate support surrounds the inner ring of beam regions and the intermediate support is surrounded by the outer ring of beam regions, desirably wherein the intermediate support defines one of the at least one aperture, and the intermediate support is positioned to correspond to the inner ring of beam regions.

[0181] Clause 14. The device according to any one of Clauses 8 to 13, wherein the plurality of beam regions includes a central beam region positioned in the middle region, desirably at the central position.

[0182] Clause 15. The device according to any preceding clause, wherein the spacer includes an internal support member disposed between adjacent elements to support the adjacent elements, and the periphery of the internal support member is surrounded by more than two beam regions, desirably wherein the internal support member is positioned at the central position at the midpoint of the plurality of beam regions.

[0183] Clause 16. The device according to any one of Clauses 4 to 15, wherein one or more lens arrays include one or more converging lens arrays.

[0184] Clause 17. The device according to Clause 11, wherein one or more converging lens arrays are configured to generate a plurality of beams of a beam grid from a separate source beam.

[0185] Clause 18. The device according to any one of Clauses 4 to 15, wherein one or more lens arrays include one or more objective lens arrays configured to operate on the plurality of beams of the beam grid.

[0186] Clause 19. The device according to Clause 16 or 17, wherein one or more lens arrays include one or more objective lens arrays configured to operate on the plurality of beams of the beam grid.

[0187] Clause 20. The device according to Clause 18 or 19, wherein one of the objective lens arrays in the objective lens array has more than one beam region among the plurality of beam regions.

[0188] Clause 21. The device according to Clause 19 or 20, wherein one or more lens arrays include a greater number of converging lens arrays than the objective lens array, desirably wherein the aperture array of the converging lens array includes more discontinuous patterns than the objective lens array.

[0189] Clause 22. The device according to any one of Clauses 19 to 21, wherein on average, the beam regions of each objective lens array are more than those of each converging lens array.

[0190] Clause 23. The device according to Clause 19 or 20, wherein the number of beam regions of each objective lens array is the same as that of each converging lens array, desirably wherein each objective lens array has the same number of beam regions as the corresponding converging lens array assigned to the same source beam.

[0191] Clause 24. The device according to any one of Clauses 16 to 23, wherein in at least one of the one or more lens arrays, the pattern of the aperture array of different beam regions in the array is the same.

[0192] Clause 25. The apparatus according to any one of Clauses 16 to 24, wherein in at least one of the one or more lens arrays, the distance between adjacent apertures of the beam regions is the same.

[0193] Clause 26. The apparatus according to any one of Clauses 16 to 25, wherein in at least one of the one or more lens arrays, the distance between adjacent apertures from different adjacent beam regions is different from the distance between apertures in the corresponding beam regions.

[0194] Clause 27. The apparatus according to any one of Clauses 16 to 26, wherein at least one of the one or more lens arrays includes apertures of different beam regions having a discontinuous pattern between the different beam regions.

[0195] Clause 28. The apparatus according to any one of Clauses 16 to 27, wherein in at least one of the one or more lens arrays, the distance between apertures within two different adjacent beam regions is the same as the distance between adjacent apertures of the two different beam regions, wherein the apertures of the different beam regions have a continuous pattern.

[0196] Clause 29. The apparatus according to any one of the preceding clauses, wherein the one or more lens arrays include a plurality of lens arrays, the plurality of lens arrays including at least two sets of lens arrays, wherein each set of lens arrays includes one or more of the plurality of lens arrays; and wherein each set of lens arrays is configured to be controlled separately.

[0197] Clause 30. The apparatus according to Clause 29, wherein at least one set of lens arrays is configured to be actuated relative to at least another set of lens arrays in at least one degree of freedom, desirably wherein at least one of the one or more lens arrays is configured to be actuated in up to six degrees of freedom.

[0198] Clause 31. The apparatus according to Clause 30, wherein at least one set of lens arrays includes a plurality of lens arrays, desirably wherein at least one set of lens arrays includes a lens array having a plurality of beam regions corresponding to a beam region ring.

[0199] Clause 32. The apparatus according to Clause 29 or 30, wherein at least two sets of lens arrays include at least one set of converging lens arrays and at least one set of objective lens arrays, desirably wherein the number of sets of converging lens arrays is different from the number of sets of objective lens arrays.

[0200] Clause 33. The apparatus according to any one of the preceding clauses, wherein a voltage is configured to be applied to the aperture array and / or the adjacent elements to supply the voltage to different beam regions.

[0201] Clause 34. The apparatus according to Clause 33, further comprising a voltage source configured to supply the voltage.

[0202] Clause 35. The apparatus according to any of the preceding clauses, wherein the element or adjacent element includes a detector array desirably including detector elements associated with each aperture, and desirably the detector is configured to face the sample position.

[0203] Clause 36. The apparatus according to any of the preceding clauses, further comprising a cooling conduit configured to thermally condition the element and / or adjacent element, desirably the cooling conduit contacts the element and / or adjacent element, for example, along the surface of the element, and desirably the cooling conduit includes a path between different beam regions desirably having a discontinuous pattern.

[0204] Clause 37. The apparatus according to any of the preceding clauses, wherein associated with the element and / or adjacent element is electronics associated with two or more beam regions, desirably the element and / or another element includes an electrode array configured to be controlled by the electronics, for example, the electronics can be remote from the element and / or adjacent element and / or can be included on the element and / or adjacent element.

[0205] Clause 38. The apparatus according to any of the preceding clauses, wherein the plurality of elements includes a collimator configured to collimate the beams of a beam grid desirably from a divergent path, desirably the collimator operates on the beams associated with different beam regions and / or beam grids.

[0206] Clause 39. The apparatus according to any of the preceding clauses, further comprising a shield, wherein the shield is configured to extend at least partially between the paths of different beam grids, for example, along the grid path, and wherein the beam regions have a discontinuous pattern, desirably such that along a portion of the path of the beam grid, the beam paths share the shield.

[0207] Clause 40. The apparatus according to any of the preceding clauses, the source includes a transmitter, and the device further includes a shield between the transmitters.

[0208] Clause 41. A charged particle device for projecting multiple charged particle beams towards a sample, the device comprising the apparatus of any of the preceding clauses and a platform configured to support the sample.

[0209] Clause 42. The device according to Clause 41, further comprising a vacuum chamber, wherein the apparatus is housed within the vacuum chamber, and desirably the vacuum chamber includes at least one cooling port.

[0210] Clause 43. The device according to Clause 42, further comprising a plurality of vacuum sub-chambers, and desirably each source is housed within a corresponding vacuum sub-chamber.

[0211] Item 44. The apparatus according to any one of Items 41 to 43 further includes a feedthrough configured to supply a voltage of elevated potential to one or more elements of the device, desirably the feedthrough for supplying the voltage applied to one or more elements of the device, such elements operating on two or more beam regions.

[0212] Item 45. The apparatus according to any one of Items 41 to 44 further includes a feedthrough configured to send a control signal to the device (desirably one or more elements of the device) and receive a detection signal from the device, such elements operating on two or more beam regions.

[0213] Reference to a component or system of components or elements that can controllably manipulate a charged particle beam in a certain way includes configuring a controller or control system or control unit to control the component to manipulate the charged particle beam in the described way, and optionally using other controllers or devices (such as a voltage source and / or a current source) to control the component to manipulate the charged particle beam in this way. For example, under the control of a controller or control system or control unit, a voltage source can be electrically connected to one or more components (such as element 300' of the corresponding component) to apply a potential to the component, such as in the non-limiting list of a control lens array 250, an objective lens array 241, a focusing lens 231, a corrector, a collimator element array, and a scanning deflector array 260. Using one or more controllers, control systems, or control units to control the actuation of a component, an actuatable component such as a platform can be controllable to actuate another component (such as a beam path) and thus move relative to another component.

[0214] Embodiments described herein may take the form of a series of aperture arrays or electro-optical elements arranged in an array along a beam or multiple beam paths. Such electro-optical elements can be electrostatic. In an embodiment, all electro-optical elements (e.g., from a beam-limiting aperture array to the last electro-optical element in the sub-beam path before the sample) can be electrostatic and / or can be in the form of an aperture array or a plate array. In some arrangements, one or more electro-optical elements are fabricated as microelectromechanical systems (MEMS) (i.e., using MEMS fabrication techniques). For example, an aperture array, e.g., the plate electrodes of an objective lens array, one or more features of a detector array, a scanning deflector array, and a collimator element array can be formed using MEMS fabrication techniques.

[0215] References to upper and lower, up and down, above and below should be understood to refer to directions parallel (usually but not always vertical) to the upstream and downstream directions of the electron beam or beams impinging on the sample 208. Thus, references to upstream and downstream are intended to refer to directions with respect to the beam path that are independent of any current gravitational field. These references are intended to correspond to the general direction of the electron beam from the source to the sample. However, these references with respect to the beam path can correspond to references with respect to the electron optical axis of the apparatus 41. For a multi-apparatus 41, the beam path direction of at least one sub-apparatus 42 (reference sub-apparatus) in the sub-apparatus 42 can correspond to the electron optical axis of the same sub-apparatus 41. Other sub-apparatus of the multi-apparatus 41 can be calibrated with respect to the reference sub-apparatus. The electron optical axis can correspond to the geometric axis of the reference sub-apparatus and, in an embodiment, can correspond to the geometric axis of the multi-apparatus.

[0216] An evaluation system according to an embodiment of the present disclosure can be a tool for qualitatively evaluating a sample (e.g., pass / fail), a tool for quantitatively measuring a sample (e.g., dimensions of features), or a tool for generating a map image of a sample. Examples of evaluation systems are inspection tools (e.g., for identifying defects), review tools (e.g., for classifying defects), and metrology tools or any combination of tools capable of performing evaluation functionality associated with inspection tools, review tools, or metrology tools (e.g., subway inspection tools). The electron optical apparatus 41 can be a component of a charged particle evaluation system 40; such as part of an inspection tool or a subway inspection tool or an electron beam lithography tool. Any reference to a tool herein is intended to encompass an apparatus, device, or system that includes various components that can or cannot be juxtaposed and can even be located in separate rooms, particularly, for example, for data processing elements.

[0217] The terms "sub-beam" and "beam wave" are used interchangeably herein and are both understood to encompass any radiation beam derived from a parent radiation beam by dividing or splitting the parent radiation beam. The term "beam" can be used synonymously with "sub-beam" and "beam wave". The term "manipulator" is used to encompass any element that affects the path of a sub-beam or beam wave, such as a lens or a deflector.

[0218] Although the present invention has been described in connection with various embodiments, other embodiments of the present invention will be apparent to those skilled in the art in view of the specification and practice of the invention disclosed herein. The specification and examples are intended to be considered only exemplary, and the true scope and spirit of the invention are indicated by the following claims.

[0219] The above description is intended to be illustrative and not restrictive. Thus, it will be apparent to those skilled in the art that modifications can be made as described without departing from the scope of the claims set forth below.

Claims

1. A charged particle device for projecting multiple beams of charged particles towards a sample, the device comprising: a plurality of sources configured to emit respective source beams of charged particles along respective paths of a beam grid towards the sample, the beam grid comprising a plurality of charged particle beams; one or more elements in which an aperture array is defined, the one or more elements each comprising a plurality of beam regions assigned to respective source beams, wherein the one or more elements are configured to operate on the charged particle beams in the beam grid of the respective source beams; wherein each element is separated from an adjacent element by a spacer having at least one aperture, the at least one aperture being positioned to correspond to the positions of at least two beam regions.

2. The device according to claim 1, wherein the one or more elements are configured to be positioned such that the aperture array is arranged along the path of the beam grid.

3. The device according to claim 1 or 2, wherein each beam region corresponds to a respective beam grid of one of the source beams in the respective source beams.

4. The device according to any of the preceding claims, wherein the element is an electrode of a lens array, desirably wherein the electrode is an electrode plate, desirably wherein the lens array comprises the adjacent element and the spacer.

5. The device according to any of the preceding claims, wherein the spacer comprises an external support provided between the adjacent elements to support the adjacent elements.

6. The device according to claim 5, wherein the external support defines the at least one aperture, desirably wherein the at least one aperture is positioned to correspond to the positions of the plurality of beam regions, desirably wherein the external support is positioned to surround the plurality of beam regions.

7. The device according to any of the preceding claims, wherein the plurality of beam regions are arranged in a two-dimensional array desirably having a pattern, the two-dimensional array desirably comprising at least 2 rows of parallel beam regions, wherein each row comprises at least 2 beam regions.

8. The device according to claim 7, wherein the plurality of beam regions comprise at least one ring of beam regions arranged in a two-dimensional ring around a central position at the midpoint of the plurality of beam regions, desirably wherein the at least one ring of beam regions comprises up to 4 rings of beam regions.

9. The device according to claim 7, wherein the two-dimensional array comprises beam regions arranged around an intermediate region of the plurality of beam regions, desirably wherein the intermediate region is at a central position, desirably wherein the two-dimensional array is annular, such as an annulus of beam regions, desirably wherein the annulus forms at least one ring.

10. The device according to claim 8 or 9, wherein the at least one ring of beam regions comprises an inner ring of beam regions arranged adjacent to the central position, desirably wherein the inner ring of beam regions comprises up to 6 beam regions.

11. The apparatus according to claim 10, wherein the at least one beam region ring includes an outer beam region ring, wherein the outer beam region ring surrounds the inner beam region ring, desirably wherein the outer beam region ring is positioned concentrically around the inner beam region ring, desirably wherein the outer beam region ring includes up to 20 beam regions.

12. The apparatus according to any of the preceding claims, wherein the spacer includes an intermediate support member that is disposed between the adjacent elements to support the adjacent elements, wherein the intermediate support member is positioned between two adjacent beam regions, such as equidistant between two or more beam regions, desirably the position of the intermediate support member corresponds to the intermediate region, desirably for example the intermediate support member surrounds one or more of the beam regions and is positioned around the intermediate region, such as a plurality of apertures in the aperture are defined in the spacer, and the intermediate support member may define one or more of the apertures through the support member.

13. The apparatus according to any of the preceding claims, wherein the spacer includes an inner support member that is disposed between the adjacent elements to support the adjacent elements, wherein the periphery of the inner support member is surrounded by more than two beam regions among the beam regions, desirably wherein the inner support member is positioned at a central position at the midpoint of the plurality of beam regions.

14. The apparatus according to any one of claims 4 to 13, wherein the one or more lens arrays include one or more converging lens arrays and / or wherein the one or more lens arrays include one or more objective lens arrays configured to operate on the plurality of beams of the beam grid.

15. The apparatus according to claim 14, wherein the one or more lens arrays include a greater number of converging lens arrays than objective lens arrays, desirably wherein the aperture array of the converging lens arrays includes more discontinuous patterns than the discontinuous pattern of the objective lens arrays.

Images